External Tax Interface - MM

Hi all,

I am working on External Tax Interface - RFC_ Calculate_taxes_Doc . while passing values thru' communication stru - KOMK and KOMP the additional fields values not comming to user exit EXIT_SAPlfytx_user_001 ( only MM trans)

I can able to get from Va01 & Fb60 but while running MM related transaction the values are not comming . Anyone can help to solve this issue ?

Thanks,

Muthu