Determining external IP for a workflow

Folks,

I've got a bit of an interesting one. Currently users can be on the network accessing GE SL viewer via simple http request, or off the network - WWW - using a https request. Problem is when it comes time to invoke a workflow and present data in a combo-box/auto-complet  e field on a form it needs to know what protocol it's using. I can easily add a prompt to ask them to click where they are and then have the option of directing the workflow internals to either an 'internal' or 'external' form builder - which I have done, but it is an extra step in the process.

Can anyone think of an easier way to do this? ie. capture the requesting IP and check for internal/external and build the forms accordingly? Once the client loads it's values, the rest of the workflow simply runs http requests on the same services as the process from then on is internal.....

hope that makes sense /customer/servlet/servlet.FileDownload?file=00P6000000e88ELEAY

TIA 

G