Wbs from internal order in MIGO

Dear All,

we want to post goods issue against internal order with movement type 261 and transaction code Mb1a and MIGO.

We are try to goods issue with reference of internal order but we are not able to enter WBS in Migo screen.

now we want to wbs come from internal order because wbs is already maintained in Equipment and Internal order.

Regards,

Mukesh