If there is a package of benefits advertised with a job and you get the job, then you should get the benefits.
If you already receive the benefits with your current position and they are the same as the benefits advertised with the new postion then HR can say that your new salary is x, but all other benefits are the same. For instance, if I am part of a pension scheme and my employer pays in 10% of salary for all employees, it won't change even if I get a promotion.
If you were not getting any of the benefits (mentioned in the job spec) before you got the promotion, then you have to be in a very strong position to insist that HR amend your terms and conditions.
Hope this helps.