This is a topic I have, lucky for some of you in this thread, have had to become a SME on, as I was in a similar situation and managed to solve it, using the methods that, surprisingly enough, the older, wiser members of the forum have been suggesting. Funny how that works...
First, brief history of my case. I was a reservist for 4 years plus. (I know that doesn't apply to many of you, but time in doesn't seem to be a huge factor for whatever reason.) I had plenty of courses and a bit of full time under my belt. When I CT'ed to the RegF, I was granted Pay Table A, Level B and then was subsequently promoted into Pay Table B, Level B. I was recieving the same rate of pay as those who enrolled in my entry program off the street with no prior service. Combined with my educational qualifications that by passes me through a phase of my training, I believed I was entitled to pay that reflected my previous service and possession of qualifications in my new trade.
Now, the DS solution... which has already been suggested. A Memo. They are surprisingly POWERFUL things. Learn how to write them.
Gather all the references you can find. I referenced CBI 204.211, ADM-HR MIL Adminitrative Instructions, Grievance Board Cases, my Statement of Reserve Force Service (CF1007), My MPRR... anything I could get my hands on to illustrate my point. As someone said, the people who deal with this type of thing are busy, and they don't have time to wade through alot of crap. So, get out a highlighter, highlight the important stuff in your references, and attach them properly to a short, concise and complete memo, outlining your case.
After you have complied your case, submit the memo through your CoC and request a "File review" both verbally on submission and in the memo. What should happen is the memo, after being reviewed an minuted by your supervisor, will go to the OR. The OR will make a copy of your Pers file and send it, along with a letter to G3 Enrollment Inquires at CFRG in Borden, requesting that your entitlements on enrollment be reviewed and any required changes be made.
Each file is then reviewed on a case by case basis by Borden. It takes around a month or so. After the file review is complete, G3 will either issue a ETP message ammendment, stating your new pay details, or a letter stating that your file has been reviewed and you get what you got.
This isn't a short process. Expect at least a month for Borden to review the file and another 3 months from the date on the message ammendment to seeing a change in your pay. My message was recieved by Ottawa on Oct 20th and I am still waiting to see the money on a pay statement. I am hoping for January, but like everything, this takes time.
I would not normally claim anything I say is gospel, but from my experiance and those of others, this is the way you do this. And let me add that your pay is YOUR business. Don't expect someone to do the legwork for you. You need to put together a case that is easy to review in order for your request to be actioned in a timely manner.
Cheers.