f-02 document number to be used in bdc ( session method ) in f-51 in the same program for another bdc using session method

Hi abap group members ,

I have a requirement in which the BDC has to be written using session method for F-02 and the document number which is generated in F-02 is used in the same program for F-51 which is another BDC . These two BDC are working separately in the same program if i manually provide the document no in F-51 . But how to use that in a single program using first BDC using session method to create Document No and other BDC to use that document number generated in F-51 .

What is the best approach to do this ?

Thanks in advance .

Rgds ,

Dave