Hi Herb
You can use the RasApi32.dll to detect a current connection and then hang it up.
The functions to use are RasEnumConnections() which will return a handle to the active connection and then use this in RasHangUp(nHandle).
I had to use the Struct class which is found in the Download section here on UT which also has some RAS examples. Also try this MS site
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/rras/hh/network/rasclnt_7iud.aspwhich is the RAS reference.
HTH
Cheers
Charlie