Exploding assembly bom on assembly order

lanemark

We currently create assembly orders for Sales orders. In some of our assembly boms we have other sub assembly boms, when we assemble the top level item we pick and assemble all the sub assemblies at the same time. We do this by exploding the sub assembly boms on the assembly order. this adds all the components and changes the qty of the parent to zero.
We have started to explode these assembly boms in advance so when the assembly order is created the sub assemblies are already exploded. unfortunately the sub assembly item number is removed. is there a way to keep the sub assembly item number in the Bom with a qty of zero?