VI04 - Shipment Cost creation - Need to pick Shipment number

Hi,

In VOFM->Formulas->Condition base value-> Routine I am updating shipping cost pricing conditions. TCODES VI01, VI02 and VI04 calls this routine to create\update pricing conditions . So I need to pick the shipment number from the routine. But I could not find any structure or internal table carrying the shipment number in the routine. In VI01/ VI02 using Get parameter ID able to pick the shipment number. But for VI04, multiple shipment numbers can be entered. I am not able to pick the shipment numbers.

So I need a solution to pick the shipment number in VI04 which is calling tcode VT10.

Regards

Harry