GATP: MATP and RBA for components ok, bu can't do RBA then MATP for header?

Hello

my scenario is the following:

- I enter a Make to Order sale order in one plant let's say PLA1

- I expect RBA to check the stock in PLA1 (MTO => there will be no stock),

- then substitute (RBA plant substitution) to PLA2 (still no stock),

- then run MATP in PLA2 and explode the BOM

But it looks like it is not working.

I read that we could use MATP,  then RBA for the components, but doing RBA (plant substitution at the MTO material level) then MATP would not be possible ?

Could anybody confirm ? Is there a workaround ?

thanks

Gilles