diff --git a/tren.py b/tren.py
index 615bae4..38829fc 100755
--- a/tren.py
+++ b/tren.py
@@ -8,7 +8,7 @@
 PROGNAME = "tren.py"
 BASENAME = PROGNAME.split(".py")[0]
 PROGENV  = BASENAME.upper()
-RCSID = "$Id: tren.py,v 1.190 2010/03/13 19:59:52 tundra Exp $"
+RCSID = "$Id: tren.py,v 1.191 2010/03/13 20:53:25 tundra Exp $"
 VERSION = RCSID.split()[2]
 
 # Copyright Information
@@ -135,6 +135,7 @@
 
 # General Literals
 
+ALPHADELIM =  ":"             # Delimits alphabet name in a Sequence renaming token
 TOKDELIM   =  "/"             # Delimiter for all renaming tokens
 
 # Shared File Attribute And Sequence Renaming Tokens
@@ -255,46 +256,48 @@
 # Debug Messages
 #####
 
-DEBUGFLAG     =   "-d"
-dALPHABETS    =   "Alphabets"
-dCMDLINE      =   "Command Line"
-dCURSTATE     =   "Current State Of Program Options"
-dDEBUG        =   "DEBUG"
-dDUMPOBJ      =   "Dumping Object %s"
-dINCLFILES    =   "Included Files:"
-dPROGENV      =   "$" + PROGENV
-dRENREQ       =   "Renaming Request:"
-dRENTARGET    =   "Rename Target:"
-dRESOLVEDOPTS =   "Resolved Command Line"
-dSEPCHAR      =   "-"     # Used for debug separator lines
-dSORTVIEW     =   "Sort View:"
+DEBUGFLAG          =   "-d"
+dALPHABETS         =   "Alphabets"
+dCMDLINE           =   "Command Line"
+dCURSTATE          =   "Current State Of Program Options"
+dDEBUG             =   "DEBUG"
+dDUMPOBJ           =   "Dumping Object %s"
+dINCLFILES         =   "Included Files:"
+dPROGENV           =   "$" + PROGENV
+dRENREQ            =   "Renaming Request:"
+dRENTARGET         =   "Rename Target:"
+dRESOLVEDOPTS      =   "Resolved Command Line"
+dSEPCHAR           =   "-"     # Used for debug separator lines
+dSORTVIEW          =   "Sort View:"
 
 
 #####
 # Error Messages
 #####
 
-eARGLENGTH    =  "%s must contain exactly %s character(s)!"
-eBADARG       =  "Invalid command line: %s!"
-eBADINCL      =  "option -%s requires argument" % INCL
-eBADINSTANCE  =  "%s is an invalid replacement instance! Must be integer values in the form: n, n:n, :n, n:, or :"
-eBADLEN       =  "Bad line length '%s'!"
-eBADNEWOLD    =  "Bad -r argument '%s'!  Requires exactly one new, old string separator (Default: " + DEFSEP + ")"
-eBADREGEX     =  "Invalid Regular Expression: %s"
-eERROR        =  "ERROR"
-eEXECFAIL     =  "Command: '%s' Failed To Execute!"
-eFILEOPEN     =  "Cannot open file '%s': %s!"
-eLINELEN      =  "Specified line length too short!  Must be at least %s" % MINLEN
-eNAMELONG     =  "Renaming '%s' to new name '%s' too long! (Maximum length is %s.)"
-eNAMESHORT    =  "Renaming '%s' to new name '%s' too short! (Minimum length is %s.)"
-eNOROOTRENAME =  "Cannot rename root of file tree!"
-eNULLARG      =  "%s cannot be empty!"
-eRENAMEFAIL   =  "Attempt to rename '%s' to '%s' failed : %s!"
-eTOKBADSEQ    =  "Unknown sequence renaming token, '%s'!"
-eTOKDELIM     =  "Renaming token '%s' missing delimiter!"
-eTOKRANDIG    =  "Invalid random precision, '%s'!  Must be integer > 0."
-eTOKUNKNOWN   =  "Renaming token '%s' is unknown type!"
-eTOOMANYINC   =  "Too many includes! (Max is %d) Possible circular reference?" % MAXINCLUDES
+eALPHABETEXIST     =  "Alphabet '%s' requested in '%s' does not exist!"
+eALPHABETMISSING   =  "'%s' has a missing or incorrect alphabet specification!"
+eARGLENGTH         =  "%s must contain exactly %s character(s)!"
+eBADARG            =  "Invalid command line: %s!"
+eBADINCL           =  "option -%s requires argument" % INCL
+eBADINSTANCE       =  "%s is an invalid replacement instance! Must be integer values in the form: n, n:n, :n, n:, or :"
+eBADLEN            =  "Bad line length '%s'!"
+eBADNEWOLD         =  "Bad -r argument '%s'!  Requires exactly one new, old string separator (Default: " + DEFSEP + ")"
+eBADREGEX          =  "Invalid Regular Expression: %s"
+eERROR             =  "ERROR"
+eEXECFAIL          =  "Command: '%s' Failed To Execute!"
+eFILEOPEN          =  "Cannot open file '%s': %s!"
+eLINELEN           =  "Specified line length too short!  Must be at least %s" % MINLEN
+eNAMELONG          =  "Renaming '%s' to new name '%s' too long! (Maximum length is %s.)"
+eNAMESHORT         =  "Renaming '%s' to new name '%s' too short! (Minimum length is %s.)"
+eNOROOTRENAME      =  "Cannot rename root of file tree!"
+eNULLARG           =  "%s cannot be empty!"
+eRENAMEFAIL        =  "Attempt to rename '%s' to '%s' failed : %s!"
+eTOKBADSEQ         =  "Unknown sequence renaming token, '%s'!"
+eTOKDELIM          =  "Renaming token '%s' missing delimiter!"
+eTOKRANDIG         =  "Invalid random precision, '%s'!  Must be integer > 0."
+eTOKUNKNOWN        =  "Renaming token '%s' is unknown type!"
+eTOOMANYINC        =  "Too many includes! (Max is %d) Possible circular reference?" % MAXINCLUDES
 
 
 #####
@@ -1070,7 +1073,7 @@
             # Sequence Renaming Tokens
             ###
                     
-            elif r[2] != "" and (r[2][0] == TOKASCEND or r[2][0] == TOKDESCEND):
+            elif r[2] and (r[2][0] == TOKASCEND or r[2][0] == TOKDESCEND):
 
                 # Parse the Sequence Renaming Token into the token itself
                 # and its corresponding formatting field.
@@ -1085,10 +1088,31 @@
                         token, field = token[:len(seqtoken)], token[len(seqtoken):]
                         found = True
                         break
-
+                    
                 if not found:
                     ErrorMsg(eTOKBADSEQ % r[2])
 
+                # Now derive the name of the alphabet to use
+
+                if field[0] != ALPHADELIM:
+                    ErrorMsg(eALPHABETMISSING % r[2])
+
+                field = field[1:]
+
+                alphabet, alphadelim, field = field.partition(ALPHADELIM)
+
+                if not alphadelim:
+                    ErrorMsg(eALPHABETMISSING % r[2])
+
+                # Empty alphabet string means default to decimal counting
+                    
+                if not alphabet:
+                    alphabet = DECIMAL
+                    
+                if alphabet not in ALPHABETS:
+                    ErrorMsg(eALPHABETEXIST % (alphabet, r[2]))
+
+
                 # Retrieve the ordered list of the requested type,
                 # adjust for descending order, and plug in the
                 # sequence number for the current renaming target
@@ -1100,7 +1124,7 @@
                 if r[2][0] == TOKDESCEND:
                     orderedlist.reverse()
 
-                r[2] = ComputeSeqString(field, orderedlist.index(target), ALPHABETS[DECIMAL])
+                r[2] = ComputeSeqString(field, orderedlist.index(target), ALPHABETS[alphabet])
                     
             ###
             # Unrecognized Renaming Token