Set non-working days on a per user level

Dear Madam or Sir,

I am a new GreenHopper User currently getting used to it and I've already created a support issue (https://support.atlassian.com/browse/GHS-117) with a couple questions which turned out to be not supported, yet.. and therefore I'm creating Feature Requests for these one by one (to keep them separate from each other).

Particularly, I would suggest that setting Non-Working days is also possible on a per-user level which means even though non-working days have been set globally, you can override this setting on a per user level (e.g. saturdays and sundays are generally non-working days for all developers, but some opt-in for 6 or 7 working days / week and therefore 95% of the team is fine with 5/days a week, the other 5% should be able to be configured as available 7d/week).

Cheers,
-J