Ubuntu – How to set the date forward on a linux server and prevent it from resetting back to the correct time

I need to set the time on an Ubuntu Server forward 1 week, and keep it there (this is for a testing environment with date-specific conditions which need to be tested/verified by the stakeholders), however when I do this (with date -s 2010-11-11T00:00:00) the time resets back to the 'real' value after about 30 minutes.

I have disabled NTP, ntpdate etc, even removed the NTP packages, disabled munin-node for monitoring et-al, but it still happens and I can't seem to figure out what is happening.

I tried setting up a script to keep the time shifted forward every minute bit it causes weird behavior/issues with Nginx and Varnish when it switches back and forward between the script runs.

Any advice?

(Sidenote: this is an Ubuntu 9.10, running on EC2)

Additional Info: There are no cron jobs running relating to time, and I am unable to access the hardware clock to try and push that forward and use that as the source….

I am kind of thinking that this is one of the idioms of EC2 – you get a 'really reliable' clock, regardless of what you do…