Calculate and post interest document

Hi Experts,

My requirement is to calculate the interest and then post the interst document for the security deposit amount(As a part of the security deposit release process).

i guess these FMs looks helpful.

1.FKK_INTEREST_CALC and

2.FKK_CREATE_INTEREST_DOC

But after calculating the interest using the first there in no way to use this calulated interest in second FM.

Can anyone please tell me how i can use these FMs to calculate and post the interest document or please suggest me any other way to do the same.

Thnx in advance:-)

Rahul.