Change field dynamically in LSWM

Hi everyone,

I have to change a LSMW, based on recording of MEK3, to select dynamically the key combination. In my record table, the field for key combination is RV130-SELKZ(02), (02) is for the second choice of the key combination list:

For RV130-SELKZ(03), I have:

How can I choose dynamically the value between parenthesis in the LSMW?

Thank you.