So, I installed this plugin and IT WORKS!
Download, Install, Insert the 2 Captcha keys and activate. That's all.
And it's very well explained and easy to install despite you have to hack some VM code ;-)
The only 'but' is that the email feature is not automatically included in the addon...
As Jan says: Email feauture is available for users who are regularly active in Phoca Forum, are regularly translating Phoca Extensions or have donated to Phoca Project...