I've invoked the field using Ctrl+F9 and put in EQ\O(Tc) , hidden field with Alt-F9, and the two characters immediately appear - as two characters if I have a space between EQ and \ , and nothing appears if there is no space; if there is a space both sides of \ then Error! appears. Pressing F9 subsequently changes nothing. I havn't tried printing, but Print Preview shows the same
Presumably I am not doing something correctly but I cannot see what.