This is not a complete solution, but it is a good start. When you do an export from JComments that you intend to import to Disqus, a format change is required. This exe is designed to read one XML-file and write the data of that file in Disqus XML file.
Start from cmd.exe and pass a source file (must exist) and a destination file (will be overwritten) as arguments. Example:
jc2disqus.exe "c:\my_jc_file.xml" "c:\new_disqus_file.xml"
The program will ask you about a post link. Type something like this:
http://www.myblogg.com/?p=[ID]
Two escape codes are accepted. [ID] is replaced with the ID of the post and [CAT] is replaced with the parent ID of the post.
If you need to do adjustments, the Visual Basic source code can be found here.