You don't tell how you did include them.
Characters that are part of the both the Courier New (to enter) and Arial (to show) characterset might work, if you enter them with alt-0-num-num-num, and if both your browser and the receiver work in Windows.
The alternative is the html-code, with ampersand and semicolon.
I'll try this here:
They all represent a-half
The ones I submitted were an enterrobang, heavy heart, Zaph double turned quotation marks, asterism, reference mark, umbrella, white smiling face, pound sign, French franc, heavy open centre cross, circled heavy rightward arrow.
? ? ? ? ? ? ?