If you want to ask Eljay a question, edit your original post in the AMA topic and add your question. If it is something a bit more private, you can send him a PM by clicking your little avatar on the top right hand corner and opening the little envelop. There you will find a page that looks like this:
Click on New Message and a box will appear:
All you have to do now is type in Eljay's name into the Add a user box, fill in a title in the box below it, and add in your question in the large box below that.
The likeliness of him answering the PM question is less than a question asked in the AMA, though.