Problem in creating Report of Invoice

Hello All,

           I've to create a report in which following is the flow...

1) BKPF-BUKRS

    BKPF-BELNR

    BKPF-GJAHR

From this I'll get AWKEY(14) ---First 10 numbers = mseg-mblnr and remaining 4 = mseg - mjahr

                                                 e,g ;- 51100000089 = mseg-mblnr

                                                          2013             = mseg-mjahr

2) MSEG-MBLNR

    MSEG-MJAHR

After entering these 2 values I'll get LFBNR

Now I've to insert this LFBNR into RSEG-LFBNR. (But Here I'm not able to link MSEG & RSEG)

3) RSEG-LFBNR

After Getting proper output I'll get RSEG-BELNR & RSEG-GJAHR

4) Now I have to Concatenate this & have to insert into BKPF-AWKEY then I will get BKPF-BELNR & BKPF-GJAHR.

I'm not getting how to link MSEG & RSEG and also how to pass BKPF-BELNR & BKPF-GJAHR into BKPF-AWKEY can anyone explain in brief.

Thanx in advance

Uday...