I'm not sure why you would want to use an online text editor in the first place.
But anyway, you need to press
& c o p y ;
instead of
Alt 0 1 6 9
Doesn't sound like a big deal to me unless you need to include the symbol several times in each sentence.
Of course, if you know all the alt-codes by heart, and hate having to look up other codes, simply use alt-codes in the text-editor on the computer you are using, then copy/paste into Bravenet text editor.