If your employers are not yet registered as Tier 2 sponsors they should read the guidance and then apply for a sponsor licence:
http://www.ukba.homeoffice.gov.uk/sitec ... sguidance/
Once they are registered (currently takes 4 months+ from the time the application is submitted) they can assign a CoS to you. The SOC code and salary will be stated in the CoS, this is not part of the registration process. It is their responsibility to choose the appropriate SOC code, they only have to justfy it if and when asked, e.g. when UKBA visit them.
Regarding the RLMT it seems that you haven't read paragraph 86 of the policy guidance. Even if an RLMT were needed details don't have to be sent to UKBA only confirmed in the CoS that it had been done. BTW - an RLMT is only valid for 6 months.
In your case the salary will have to be the greater of £20k or the minimum stated in the code of practice