UC_OBJECTS_NOT_CHARLIKE in FM SAP_CONVERT_TO_TEX_FORMAT

Hi,

I am creating an internal table with table type MARA and I am populating all the records into it.

I try to use FM SAP_CONVERT_TO_TEX_FORMAT  to add field separator between the records.

But I get a runtime error "UC_OBJECTS_NOT_CHARLIKE"

For the statement
   "IF ... op1 CO op2 ..."
only character-type data objects are supported at the argument position
"op1".

In this case. the operand "op1" has the non-character-type "s". The
current program is a Unicode program. In the Unicode context, the type
'X' or structures containing not only character-type components are
regarded as non-character-type.

I found that there is a field STFAK(Stacking factor) in table MARA whose internal type is "s"

This FM works fine for table BKPF.

Is there any way to resolve this problem?