nopCommerce 2.40 Admin Product - how to Add Product Documents (.pdf, .doc, .vss) in admin section

I want to add different types of documents to the product in admin section. I will appreciate if anyone can reply to this.

I found some help here (but it is not working): http://stackoverflow.com/questions/9791635/nopcommerce-2-40-admin-product-edit-addition

Did you ever figure out how to get this added in? We are also in the need for this feature and I started working on the integration into 2.50 today, and i'm getting pretty close to getting it all figured out. Not too familar with MVC yet, but i'm picking it up fairly quickly.

There is an extension that has been used to add PDFs as product specifications. Check this
You can also insert PDF within the HTML description.