Output Control Conversion between SAPScript and Smartforms

I am designing Smartforms to replace standard Sapscripts. In standard program all communication data are in the structure NAST, and then, it put into the structure ITCPO. I found two structures in Smartforms, SSFCTRLOP and SSFCOMPOP,

so I just want to know how can I convert it from ITCPO or NAST. ¿there are function modules for that?

Thank you