Dear Samir
Ask ur ABAPer to make a driver pool program for that smart form which calls the Payslip data & create a report where we can run the payslip to display with that custom smart form.I hope u have already provided the layout & all stuff to ur ABAP team.,
Make sure that u don't use this Smart form to call in ESS too. This works only for R/3 users. For ESS u need to follow the feature EDPDF which I've mentioned earlier
Just try & let me know...In the meanwhile check this link too
Smart Forms - ABAP Development - SCN Wiki
Hope this Info
will be useful
Cheers 
Pradyp