Material Replication error from ECC to CRM

Hi Experts,

I facing very odd error when i am trying to replicate material Order from ECC to CRM .

1. I have created  organization in CRM say ZAR1.

2. When a material order (Material type : L001) is created in ECC then BDOC "Product_Mat" get executed and Material get replicated in CRM for same organization type .

3. But the issue come when i select differentmaterial 

say EOOOO56541 then again BDOC executed and give me error Material already exists , so i want to remove that error , i want this material get overwrite instead of giving error "Material already exists"  for same organization .

Please please help , point for helpful answer .

Regards ,

Rishi Verma