Looks like this isn't possible. However, an acceptable workaround is to enable SSO instead. Assuming that your LiveCycle server is on a private network you can then send the current user's login Id or unique identifier to authenticate. So long as they're in the ActiveDirectory database then they're ...

Our LC server is setup to authenticate with Active Directory. I have a C# application that is calling SOAP services on the server. I'd love to have my application pass the current users credentials instead of using basic authentication. Can this be done?