Hey Olivier, do you read my blog ? Here is the answer to your question, but this solution is not official
Link to Innovative Technology Weblog » How to relocate your Groove 2007 files to another disk
I am an experienced Team Leader & Distinguished Solution Architect with a passion for shipping high-quality products by empowering development team and culture toward an agile mindset. I bring technical vision and strategy, leading engineering teams to move product, processes and architecture forward.
Team Leader, Distinguished Solutions Architect