Roundabouts in InRoads.

I need to create a surface model of a stretch of roadway with two roundabouts.  And I do not have a Roundabout add-in or extension for InRoads.  I found the following post on this in the old discussion groups, saying it can be done and with some quick words of advice.

http://discussion.bentley.com/cgi-bin/dnewsweb.exe?cmd=article&group=bentley.inroads&item=13848&utag=

Can someone expand on how best to proceed with modeling such a roundabout, or direct me to a resource that would help?

Thanks,

Brian

InRoads 08.09.02.16

Microstation 08.05.02.35