24 hour clock in Sunbird

[Rick]

I have searched everywhere in Sunbird. There is no Help, other than 
Release Notes and About. The site is uninformative. I have searched 
Ubuntu 8.04. Nowhere have I found a way to change the displayed hours in 
Sunbird according to the 24 hour clock. The selections for appointments 
are 24, but the display remains AM and PM. Would someone know how make 
to make the change to a 24 hour clock?

Thanks.

Rick