Dynamics GP - Integrating to Dynamics GP-Salesperson ID on SOP line item detail does not integrate

SOP Line Item Salespersons require a Commission Record, or else GP will automatically remove the SRID from the Line Item.

Ensure that you setup an integration to add a corresponding commission line item for the Salesperson you are trying to integrate to the SOP Line Item.
There is a field in the sop header mapping for "Create commissions". Ensure it is set to "True"