Hi hmalkan,
You need to manually do what the "Remove Code" button in IP07 is doing. Here is a general outline, but I have not done this in a while, so I might be missing a step:
1. Save from template as source files
2. Open manifest.xsf, find the <xsf:file> section referencing the script.vbs file. Remove those lines from the manifest.
3. Delete the script.vbs file from the source files folder
4. Save and close all files. Right-click manifest.xsf and select Design. Try to change the code to JScript now.
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge