Business requirement:
Internal requisition needs to be created in Inv1 in OU1(Destination organization) and the material needs to be procured from Inv1 in OU2(Sourcing Organization).

Setups
1.    Define Location Loc1 and attach Inv1 to it.
      Define Location Loc2 and attach Inv2 to it.

2.    Create a new customer Internal Customer and create sites in both the Operating unit.
Go to OU2 OM responsibility and create a bill to. Attach the Loc1 and organization Inv1 in Internal Tab

Go to OU1 OM responsibility and create a bill to. Attach the same Loc1 and organization Inv1 in Internal Tab

3.    Follow the other setups and processes as defined @
http://www.oracleug.com/user-guide/purchasing-overview/internal-requisit...