Sign-triggered reclassification per FS item

Dear all,

I use method reclassification with using sign of FS item set. Selection contains two FS Items: for asset and liability. The first item has sums with a positive sign, the second - with a negative sign. In the method of reclassification, it is required to take into account the sign of the sum of these two FS items. In fact only one of them is taken into reclassification, depending on the sign of the rule. Tab "Dr/Cr sign" and "Balance per characteristic" is empty.

How can use the sign of item set and eliminate one FS item from another?

Thank a lot for your advice