Header Condition value getting cleared when make Carry out new pricing

Hi all,

We have a Header Condition (ZICD) in our pricing procedure.

When booking the Sales order we are entering the condition value (ZICD) at header and its coming in Item level also.

While creating billing document through VF01 if we make Item level Update (B---Carry out new pricing) by update button, the ZICD condition getting cleared, ie it is coming as zero value.

Pl. help how to handle this.

Sarran