Okay, let's take it one step at a time. The way Impulse works is that it automatically associates the CD keys when you buy something to the email address you used (which should therefore match the email address that you used to set up your Impulse/SD account).
Did you buy with Paypal that has a different email than the one in your Impulse account?
If the emails are the same and you launch Impulse and log in with that same account, do you see the games in the My Games tab?
If you click the blue ? in the top right in Impulse and select "Register a product", do you see Sins and Entrenchment in the list that pops up?
