I just dealt with registering my e-certificates last week. You have to call though it cannot be done online. I finally got it done, after 15 minutes and being put on hold several times, and being told several times there was no way to do it. It can be done!!
I was insistant and asked to speak to the supervisor. The CM actually refused to transfer me to someone else but did put me on hold and I guess found the answer and did it for me.
I tried to access the PH section and cannot get in this morning, however I was able to get in all weekend. (was trying to price out 2 quick-2 day trips
during F&W & Xmas season)
Also as a side note, there are MANY bugs in the Disney website, so if you cannot do something, like log in, make ADR, check your reservation, etc, just keep on trying! Do not give up!