In my experience, setting up an actual editor preference in Integrity is not a viable solution because then it becomes the editor for all file types. Try opening a MS Office document with that!
But I've found a trick to ensure that the Integrity client uses the same associations as Windows 7's double-click: For Integrity Preferences, do not use "Use System Editor". This would be the logical choice but doesn't work because of the confusion between Open and Edit in Windows 7.
Instead, specify an "Editor" but use "explorer.exe" for the program name. Now Integrity will launch Windows Explorer which will use its association the way you expect.
