Steam/Sonar

I purchased Sonar Producer x3e at Christmas via Steam and then the platinum yearly membership to upgrade it the day it became available via Cakewalk store.
 
Now today on steam the yearly membership has appeared for only $99. Woulda been kinda cool if we had a heads up that such a good deal was coming.
 
Can I enter my platinum key from my cakewalk account into Steam and apply the platinum upgrade to my steam account?
It is good having everything in one place in Steam so would be cool if my key will register in steam.
 
 
All that said - I am very happy with Sonar.
Been doing some great sounding recordings and really enjoying the stability over older versions I had used before.
 
 
EDIT: Oh yeah - I cant log my main account into the forums - something is broken so I have to use this secondary one still.
I have sent an email about it but received no response/fix.