As far as i have learned (which is very little so far) you just need the basic gestures.
so work can be found here http://www.signbsl.com/sign/work
ambulance here http://www.signbsl.com/sign/ambulance
and service here http://www.signbsl.com/sign/service
you would have to start with "I" which is as simple as pointing to yourself.
Hope this helps
pd