I find myself in somewhat the same situation, only with different circumstances. The box is located in UTC-5 (EST) and I'm located in UTC+1 along with everyone else who uses the forum. I did the decent thing and filled "Server time zone" with "-05 EST", and when I configure my own account to be "+01 CET", it displays nicely. Only my problem is then: it only displays nicely if you have an account with a correctly configured time zone. Most of the forum visitors are anonymous including when they post, and these are neglected because there isn't another box in the "Options" menu that says "Number of time zones with which to adjust the server time". The thing is, if I simply cheat and put the wrong time zone under the first option, anybody who have rightfully filled in +01 CET will get wrong times because of the assumption that the server's time zone relative to the user's time zone is actually real.
Has anybody done anything like this before? It's only adding a number to the time if a person isn't logged in, really.