Hi João

The problem seems to be related with having the ã character in the path and how encoding is handled in batch files (Integration Studio creates a batch file called compile.bat that is used to call msbuild). As a workaround you can try to save the extension in another folder for which the path doesn't include accented characters.

It would also be great if you could submit feedback (Integration Studio's Help menu -> Submit Feedback) regarding this issue so we can treat it as an Integration Studio bug and fix it.

Please let me know if it solves your problem.

Thanks.