The problem about 2004/38/EC is, that each and every embassy has its own interpretation and deals very differently with it.
This is not limited by country but by embassy - so while the Dutch embassy in London may be great (I don't know, just an example), the Dutch embassy in Dublin may be a pain. (again, just an example)
I know nothing about Cairo, thus you will have to plough through the embassies there to see for yourself. (Give them a call and see what they say. Attempting to change their attitude by mentioning 2004/38/EC usually leads nowhere.)
As you already lodged an application with the Belgian embassy there, you are stuck with them for now - you can only apply for a different Schengen-visa after 6 months passed, or your visa was granted and expired... (They will find out through the SiS!)
The length of the visa is not mentioned in any law, thus you may have to apply for each and every visit, if they refure to give you a multiple-entry for a longer period.
I went through the same pain in Dublin, as my wife is Lebanese and we want to go for the weekend sometimes. No dice - we had to apply each time.
So - good luck in your endeavors!