I've never heard of an IRCd that provides any way of a client knowing which ops are also +v. The only way to tell is to get the /names #channel list or /who #channel list whenever someone deops. The IRCd keeps track of who all is +o and +v but there's no way I know of to retrieve that information from the server. From what I can recall when I tried to add @+nick to /names years ago, that breaks some clients which do not expect to see two (or more) modes before a nickname, since they would expect only the first character to be a mode character and the rest are all part of the nickname.
Again, as Collective said, this is not a mIRC bug; it is a "feature" of the IRCd.
