Accessing an asp.net web service with classic asp

My company is considering working with another company on a particular module. Information would be sent back and forth between us through my web service. Thing is, my we开发者_开发知识库b service uses ASP.NET, and they use classic ASP. Everything I've found online says (it's a pain, but) they can communicate, but I'm not clear on some details.

Specifically, do I have to enable GET and POST on my web service? If I don't have to, but could, would enabling them make the communication significantly easier/better? And finally, GET and POST are disabled by default because of security. What are the security risks involved in enabling them?

My first question should be "Why use Soap?". The simplest common demoninator that you have between the two is XML so thats a given. However the choice of transport can be as simple as an single .ashx or as clever as WCF service.

Since your first consumer is using ASP why use a technology that makes it difficult for them?

The true bottom line here is what are your security requirements?