Custom Web Service Application

[Amid]

Is it possible to instruct IIS to use external process to use when serving
user requests.

I'll try to explain the problem. I need to develop application that will
expose some web methods. So obviously this application must be made as web
service. BUT. In addition this application can be used as standalone server,
so there must be a posibility to start it manually (as windows service,
console app etc.) and then close it manually, without waiting while this will
be done by IIS itself.

So it would be nice if the is a possibility to for IIS to use my external
process for serving user requests.

Any help will be appreciated.
Thanks.