Using the following settings
set textwidth=40
set fo? -> formatoptions=croql)
set comments? -> comments=sO:* -,mO:* ,exO:*/,s1:/*,mb:*,ex:*/,://
set ci
I don't think it is. The comment formatting with 'comments' and 'formatoptions' only recognises when the comment string is at start-of-line. The comment starting in the middle of the line is only recognised by the syntax-highlighter, not the formatter. For this reason I don't think it's possible in Vim as shipped. You might be able to find a plugin to do it, but a cursory search on the Vim website didn't turn up anything useful.