Then UI Messages are the best method. You are in for a real treat if you haven't ever dealt with these before. 🙂
Basically j_dodek had the right idea. If you do his suggestion then you can have the status bar update with the correct values. I am attaching his sequence in 3.1. I didn't run it or anything but it looks like the PostUIMessage is being used instead of the PostUIMessageEx. You can read about them in the help and the differences. The Ex is the newer version of the function and should do the same thing.
If you don't want to update the status bar and you want your own controls then you have to change some code in the OI to handle the UIMessages. Here's a link that talks about UIMessages:
http://zone.ni.com/devzone/cda/tut/p/id/4532 It's very helpful for undestanding what they are and how they are used. Basically they are the best, NI Recommended, way of getting info from sequences to the OI and vice versa.
If you have taken the TestStand course then there is an exercise that does exactly this. In the old course it was in TestStand II manual. I don't know about the new one. If you need help with it let me know as it requires callbacks and references and such.
Regards,
