Retention of the original BATCH NUMBER during material transfer from Plant

Dear All

We are implementing SAP AFS 6.0.In AFS batch numbers are defined at Plant level.We have two manufacturing plants"MFG1 and MFG2".. Material produced in these plants should have a prefix of plant in the Batch numbers e.x. MFG1001,MFG2001 etc.This we have done theu user exit.

Material manufactured is sold thru depots(Plants).Depot names are DEP1,DEP2---etc.When we transfer the material from manufacturing plant to Depot plant the batch number of the material is changing for ex batch MFG1001 changes to batch no. DEP1001.

**We want the original batch number of the manufacturing to be carried forward during material transfer from mfg. plant to Depot plant.

How should we go about.

Thanks in advance

Suryanarayana t