Picking group not filled on storage unit

Hello all,

We're using a 2 step picking process in our warehouse. We create a picking group via tcode VL06P and create the transfer orders via tcode LT0E.

So far so good. When the stock is at the interim storage type there is no link between the handling unit and the picking group. In table LEIN there is a field REFNR which is the picking group but it's not filled. Does anyone known how or where the copy should be done of the picking group to the storage unit?

Thanks in advance.

Rgds, Patrick