First of all, service admins can always talk in +m channels with or without +vhoaq. Second, your IRC client will always show things you say whether they are accepted or not. You can check your Status window for error messages like #Blah You need a {voice|registered nick} to speak.
To test the first option, do /mode <yournick> -ox to de-op (-x clears your vhost), then try again.
As codemastr says... that's what +mu does... only ops will see the "<IRC> User: msg" part, it's a feature... It only happends if both +m and +u are set. You can shut it up however by just banning +b IRC!*@* :).