Changing SSR to 1201 and back to 1200

[overload]

If transitting the LAX Bravo via the special rules airspace transit procedure, whichs requires an SSR code of 1201 - should I go back to 1200 having the bravo?
Pilots are encourged to make position reports on 128.55 during the transit - I wasn't really sure what to say - so said something like "L A X traffic Mooney 1 Mike Sierra, Imperial Highway 4500 feet northwest-bound VFR - L A X traffic"
I think it's basically just like using CTAF - but was a little unsure how it would be used in real life?
Thanks
Eugene

[Keith Smith]

Your CTAF announcement sounds fine to me. You should go back to 1200 once you leave the SFRA.

[overload]

Thanks Keith!
Eugene