LSMW Custom program for updating picked quantity in outbound delivery

Question

I have been tasked with creating an LSMW that will update the picked quantity in an outbound delivery.  I originally thought of using a recording on transaction vl02n, but I need the LSMW to work with variable amount of item lines. 
Through some research I figured out that FM WS_DELIVERY_UPDATE_2 can update the picked quantity.  I have successfully created a custom program that calls this FM. 
I have created what I believe to be the correct entries in the SXDA0, SXDA1, SXDA2, and SXDA3 tables to make my custom program work with LSMW.  I am able to find my program in the "Maintain Object Attributes."  I am also able to "Maintain Structure Relations Step" (screen shot attached)  I am currently using VBKOK and VBPOK for the header and line item structures respectively. 
My difficulty is converting the data.  I have tried everything from having no conversion rules to mapping many fields and I always receive the following error (screen shot also provided).
Error analysis
The statement
     "Move src TO dst"
requires that the operands "dst" and "src" are convertible.
Since this statement is in a Unicode program, the special conversion
rules for Unicode programs apply.
In this case, these rules were violated.
Program /SAPDMC/SAP_LSMW_CONV_FORMS
Include  /SAPDMC/SAP_LSMW_CONV_FORMS
Row 1,080
Module type (FORM)
Module Name TRANSFER_RECORD
Since I have run the conversion with no conversion rules I am very confused as to why I am still receiving this error.  Any insight would be greatly appreciated.

Answer 1

For anyone I have uncovered some interesting things about my issue.  I started going through the conversion code piece by piece trying to figure out what data element the system was choking on. 
After digging though the program and using the debugger I found out that the issue was in FORM transfer_record. 
ASSIGN (g_record) TO <l_record>.
     CASE g_objecttype.
       WHEN '01' OR '02'.
         gt_buffer-record = g_record.
         gt_buffer-data = <l_record>.
         APPEND gt_buffer.
If this LSMW was working
g_record = 'VBKOK'
<l_record> = 'VBKOK'
But what is actually happening
g_record = 'VBKOK'
<l_record> = "Structure of some sort
I do not know why this is happening since the field symbol is being assigned right before this piece of code.  Any suggestions are greatly appreciated.