Index: generic/nsf.c
===================================================================
diff -u -r4d1efbac0cfc34dc7f0bfcb13749182050db26a6 -r9f51576de17e47b9495ae7ceea1340bc8d200507
--- generic/nsf.c	(.../nsf.c)	(revision 4d1efbac0cfc34dc7f0bfcb13749182050db26a6)
+++ generic/nsf.c	(.../nsf.c)	(revision 9f51576de17e47b9495ae7ceea1340bc8d200507)
@@ -10174,19 +10174,11 @@
       INCR_REF_COUNT(paramPtr->converterArg);
     } else {
       
-      /* option identifies a user-defined converter, implemented as a method;
-	 user-defined converters are not permitted under the parameter types
-	 alias, forward, and initcmd */
-            
-      if ((paramPtr->flags & NSF_ARG_METHOD_INVOCATION)) {
-	NsfPrintError(interp, "Parameter option '%s' not allowed for parameter type '%s'",
-		      option,
-		      paramPtr->flags & NSF_ARG_ALIAS ? "alias" :
-		      paramPtr->flags & NSF_ARG_FORWARD ? "forward" :
-		      "initcmd");
-	return TCL_ERROR;
-      }
-      
+      /* 
+       * The parameter option is still unknown. We assume that the parameter
+       * option identifies a user-defined argument checker, implemented as a
+       * method.
+       */
       paramPtr->converterName = ParamCheckObj(option, optionLength);
       INCR_REF_COUNT(paramPtr->converterName);
       result = ParamOptionSetConverter(interp, paramPtr, ObjStr(paramPtr->converterName), ConvertViaCmd);