Need Function Module - Urgent

Hi Experts,

Need a function module which populate the lfa1 with input parameter BElnR.

I need field lifnr, name1 from lfa1.

Need another FM which populate the SKAT with input parameter belnr.

I need field saknr, txt20 from skat.

Guys i have tried using select query to fetch these, howerver the performance is very slow as im querying bsis and bsak tables. I have used for all entries and also tried creating a view, that was not sucessful. Kindly provide me a solution.

Regards,

Senthil