How create a product in CAA with a CustomerExtension ?

My 3D-Exp version is V2018.

My company has CustomerExtension implemented on product. If I create with CAA API a product (using CATPrdFactory::CreatePrdFactory, and CATIPrdReferenceFactory::CreatePrdReference) the product created has not the CustomerExtension associated to it.

My questions are :

how to create the product with CustomerExtension ?

If it is not possible How can I add with CAA these extension to the product I have created with CAA?

Thanks for your answer !