I have dealt with this with this in the past by using two foreign currency journals - can be used in AP or AR and done in whichever direction necessary to clear the balance.  It means the offset in foreign currency is also zero so you don't end up with a foreign balance remaining either.  Huge pain though to have to do this   

1.

Dr. AR 1 EURO (whatever currency)

Cr AR 1 EURO  using exchange rate 1:1

2.

Cr AR 1 EURO

Dr AR 1 EURO using whatever exchange rate is necessary to bring the home currency balance to zero