Salaam Ahmed
If there is a exchange rate difference between the day you posted the invoice and the day you are clearing it, it is bound to post the Fx. Rate Differencec
a) The only option is that when you clear, you enter the Fx rate manually, which should be same as what was there on the date of Invoice... For this, the "Max Exchange rate deviation" in OBY6 must be enabled
But this can be tedious.. So, may be you can have a Z program which will force same Fx rate.
b) Apart from this, the workaround is to let the system post and then you re-class it at the end of month, with one consolidated posting
I can only think of these options
Rgds
Ajay M