Got it. It looks like for my purposes it will be easiest to implement it using AD/Local windows accounts. I did try to implement it by extending the soap headers but I couldn't make the refrence in VisualStudio work anymore and I couldn't make the webservice client connect.
My current plan is to create one user designed to access the web services and then embed that user's login information in the web services client. This will secure the webservices againt access by the general public. Any other access/permissions issues will be handled at the application level. So for my application I will have a seperate login process which will then classify the user's roles and permissions. In the background the webservice client will use the windows account in order to be allowed to make Webservice calls.