Linking GRC system Activity to CRM Opportunity

Hi,

We have requirement to link GRC System activity to CRM Opportunity.

GRC Activity is of length 50 characters and when we saw the length in DOC_FLOW its of length 70 characters

When we tried to add the GRC activity by CRM_DOC_FLOW_MAINTAIN_OW method, its not updating and its giving message as 'WRONG_TRANSACTION_TYPE'.

We used following code:

           ls_doc_links-brel_kind = 'A'.

       ls_doc_links-brel_mode = 'A'.

       ls_doc_links-reltype = 'ZZZZ'.

       ls_doc_links-objkey_a = lv_guid.

       ls_doc_links-objtype_a = 'BUS2000111'.

       ls_doc_links-objkey_b = iv_activity_id.

       ls_doc_links-objtype_b = 'BUS2000126'.

       ls_doc_links-vona_kind = 'A'.

       APPEND ls_doc_links TO lt_doc_links.

*-- update docflow

       CALL FUNCTION 'CRM_DOC_FLOW_MAINTAIN_OW'

         EXPORTING

           iv_header_guid = lv_guid

           iv_ref_guid    = lv_guid

         CHANGING

           ct_doc_links   = lt_doc_links

         EXCEPTIONS

           error_occurred = 1

           OTHERS         = 2.

and then we have saved and committed the changes.

Can you please say is there any length restriction for Transaction category 

'BUS2000126' and what is the alternative way to make it done.

Regards,

Karthik.