Function L_TO_CREATE_TR

I am trying to call function L_TO_CREATE_TR and get it to create a TO. I enter all the data in the header import parameters, and fill in the record IT_TRITE and it successfully creates the TO. However, I cannot find where I fill in the ZEUGN (certificate) field in IT_TRITE. This is critical for our products.

Has anyone been able to call this and correctly populate the inputs to create a TO and get this field populated?

I have also tried using the tables T_LTAK and T_LTAP_VB - and populating ZEUGN in T_LTAP_VB, but I get an error message....

Data for storage type search is not defined (E

Message no. L3007

When I try using these same two tables along with the header input parameters and fill in the details in IT_TRITE - it posts. However, ZEUGN is still not getting filled in.

Does anyone know what I need to do to get this field populated? I am creating the TO after creating a material document for a GR against a purchase order.

thanks,

Chip