Picking lower-level Handling Units via RF Transactions

Hi experts

How can I randomly pick Handling Units to my transfer orders using the SAP RF transactions?

I am trying to go into my warehouse and randomly pick boxes which are nested into a top level pallet HU which is the Storage Unit in the Storage Bin.

Pallet = Top Level HU = Storage Unit

Box = Lower level 'nested' HU

I know this is possible when confirming a Transfer Order using LM12 to remove lower level handling units from a Storage Unit. This can be done using the 'pick handling unit' functionality.

I have not been able to see how this can be done using the RF LMxx transactions.

Ideally I would like to scan the lower level HU's and pick them onto my Transfer Order using my handheld device and SAP LMxx transactions.

Please advise

Edd