IPC variant config

Dear experts

My client has R3 4.5 and CRM 5.0.They want to use configurable material in their B2b scenario.

I have the following question

1. It it possible to Model the product in R3 and download the knowledge base Runtime version to IPC?

Some one told me R3 4.5 is not compatible to CRM 5.0. So I can not model the product in R3 and I have to model the product In CRM using PME.

But Previously I read in this forum CRM 5.0 can not be used for configurable product with out R3 back end.

I don’t know which statement is correct. I really appreciate if some one helps me to solve this issue.

Thanks