You have to create another character on your server and mail them to your main and alts. If you are full on your server G I will log on to your server and send you one. I have free slots on all servers. PM me the name of server, name of character, and name of faction if you need me to help you get a CE banner. It is unfortunate but, this is the only fix for this at this time. Just chalk it up to yet another reason to see how substandard SWTOR is compared to it's competition.
Yeah I have 1 free slot left, so I might have to do that 11 times (thanks for the offer though), but it's more the principle and the sheer flipping shoddiness of them just seemingly not bothering to get it to work.
It's also slightly made pointless by all the people endlessly generating these banners and then selling them on the auction house, which doesn't really make them "CE" anymore, just another banner.