Wage Type Valuation for Australia

Hello Everybody

I have a WT in IT-8 say 9001 with Rs 10000

Now whn i save WT say 9014 in IT - 14 it should automatically take 10% of 9001 WT...

I have tried but it is working for India not for Australia....as INVAL feature is only for India ..how can i do it for Australia ....I have tried using PRZNT & UNITS Feature

but in that we have to enter % in Number field to the derived amount...

I don't want to enter % in Number field , directly it should catch the %

Ny suggesstions on that.. Please guide me