[Ubuntu-PH] Use of Ubuntu trademark on T-shirts?

[Ubunterror]

Hello, just a question. I've implemented the use of Dapper on all our
company workstations, and likewise I'm advocating Ubuntu to our clients
as well. I plan to give out T-shirts this Christmas, and I'm thinking of
printing our company logo, followed by "powered by Ubuntu" with the
Ubuntu logo on it. Can I go ahead with this without further permission?
I emailed trademarks at ubuntu.com last week, but still no reply.

Thanks
Alvin