Problem in bulk material

We have defined one storage type '004' as bulk storage type in our Warehouse. We have done all the required configuration.

WE have created one magterial for this storage type and assigned bulk type indicator in the material master.

MIGO has generated the T.R. But when we try to convert TR to TO with LT04 t-code we are getting the following error

"No destination storage bin to be found in storage type 004"

But we have created the storage bins for this storage type and we are able to see the list of bins in t-code LX03.

When we enter the bin no manually in LT04, we are getting error that storage unit type GB is not maintained for material "xxxxxx"

what could be missing?

Also please clarify whether storage unit management is mandatory for bulk materials?