DSM-BRFPlus Function Error when called from Workflow

Hi All,

We have 2 Systems System A (CRM System) and System B(ECC System),

BRFPlus is hosted on System A and using DSM,

We have declared System B as the Managed System and
linked our BRFPlus Application to System B, we were successfully able to access
Data Types and Function Modules in Managed System(System B) through Procedure Call
Expression and Run Simulation.

There is a Workflow in System A(CRM System) which needs to
access the BRFPlus Function using the Function ID but is failing at the point
where BRFPlus function is making a Procedure call to function in System B
(Managed System).

Error: "Unknown exception raised
during the processing of static method call <Procedure Call Name-Calling the Function Module in Managed System>"

We followed the below Steps using videos on http://scn.sap.com/docs/DOC-29158

1. Created RFC Destination for XFA System(ECC
   System) in CRM System(CRM System)
2. Used Tcode STRUST in YCA-200 to Export and Save
   the Key Certificate
3. Used Tcode STRUST in XFA-100 to Import the Key
   Certificate
4. Used Tcode DSM and added the XFA System as
   Managed System using RFC Destination created in step 1.
5. Linked our BRFPlus Application(YCA System) to
   the XFA Managed System using the Add button
6. Created Rules in the BRFPlus Application
   consisting of Procedure Calls to Functions in Managed System, saved activated.
7. Tried invoking the BRFplus function from
   Workflow using Function ID, Workflow gives error at the point where BRFPlus
   function makes the Procedure Call to Function in Managed System.

Please help if we have missed any important step which can help us get rid of this error.

Thanks and Regards,

Neha Ashokkumar Singh