this doesn't looks good, when A is a kind of variable and s'hould be in italic mode. \mathaccent`~A is the better way.
By trial-and-error I worked it out. I need a combination of spaces and right-arrows (or up arrows) to get back out of \textmf mode. Very slow and -- for me -- highly error prone. Your way looks quicker and more certain.
Hmm... actually, a way that I find easy to achieve the above is as follows: enter math mode, hit Ctrl-M, type "A", hit right arrow (you exit text-within-math-mode), now select the A that you entered by using Shift+left-arrow, then do a tilde on it with an Alt-p-& (i.e. Alt-p-Shift-7) or by selecting it from the math panel... maybe this will help..
nirmal
