How to Create PR from exeternal SQL Server through IDOC

Dear all,

I am in trouble while creating PR from exeternal SQL Server through IDOC . although I have created PR from TCODE we19 giving input as well as from function writen below

My scnerio is from external system(Sql) want to send data to sap to create PR return PR No to SQl Server

Not having idea how to do

Basic Type for Idoc : PREQCR01

Message Type : PREQCR

Function Module : BAP_Idoc_Input1

Thanxs in Advance