change purchasing output control (from sapscript to smartform) Qusetion!

I want to print a Purchasing Documents by smartform.So i look for system standard program "SAPFM06P"->FORM ENTRY_NEU.

In this form i found 2 function:'ME_READ_PO_FOR_PRINTING' and 'ME_PRINT_PO'. who can tell me the useful of function?(is it standard print function to sapscript?)

thanks