BW Replacement path variable on 2 different info object

Hello,

I have a requirement where i have to do replacement path from one query to another.

Source query gives doc number (0AC_DOC_NO char 10) and all this is then used to replace a variable on the main query (0BILL_NUM Char 10)

But it gives me error saying the replacement path variable cannot be replaced. Brain 442.

Is it not possible to replace the values from 2 different info objects?

Thanks

Ritesh