I'm glad you got it working, but it really should have worked in XP as well as in Windows 7, and with CVI 2009 as well as with CVI 2010, as long as you use the Greek character set on the control.
For example, here's a basic .uir that I created in CVI 2009 with such a control. I was able to successfully copy the text from the control in this .uir and paste in onto Notepad, in both XP and Windows 7.
Luis