Many thanks James, once again, if you cannot read, you have these problems. Looking more closely at http://mapguide.osgeo.org/downloads.html you see exactly what you suggested.
Extract:
Note: The released MapGuide Studio will disallow connecting to the MapGuide Open Source 1.1 server with a "The Studio version is incompatible with the site version" error dialog. To resolve this issue use one of the following methods:
If you have a licensed version of Studio download and install the patch (md5: cde783d5207ec22d11fcc185825fde72). The patch will work on both the released and SP1 versions of Studio 2007. (If you overwrote the Autodesk.MapGuide.Studio.Site.dll file for RC1 and need to get the original file back, it is available here md5: 92839a0fc3b87541f23adaf4d836f2ed.)
If you have an evaluation version of Studio, you will need to do the following:
1. Download the new Autodesk.MapGuide.Studio.Site.dll from here (md5: 58aa5c890ad91e7df34801e54abf25d8).
2. Unzip the file to the Studio install location.
Once the patch is installed, Studio will be able to communicate with both 1.0 (MapGuide Enterprise or MapGuide Open Source) and 1.1 servers.
It works just as you said,
Many thanks again, and now for some EXCITING testing
Ivar
PS Have been working and developing with MG since its birth a few years back now and 'What a product'
Thanks again!