I need to disable check-in operation for several projects in my solution. I need it to ensure myself from uploading changes to projects which I don't want to change. Is it possible with Team Explorer?
TFS only tracks changes that are made through Visual Studio. In your case, you need to edit the files locally, but without VS knowing. Unfortunately, this is difficult, because your converter is running in VS.
The steps would be
Some risks associated with this. This is a huge pain if the SLN files get changed very often, because your local changes will be overwritten. This cannot be avoided however, because this problem would still exist if you had them 'checked out' the normal way. You will not be able to add/remove projects to the SLN because your VS version is wrong. you will need to get someone with vs 2008 to "Add..." the project, then you'll have to get latest on the SLN and run the conversion steps again.