I was searching for this on back berfore Christmas with zero results. I doubt they'd be on the Oakville system for coverage reasons, but for logical reasons being operated by Oakville Transit it makes sense. The way transit drivers tend to talk regularly I'd have thought this would be an easy one, but not so far.
Continuing the investigation here......
EDIT: Just heard an icall on the Oakville system that sounded like a Milton driver (801, which I believe is a Milton bus #) talking about a problem with the coach, and whoever he was talking to saying "I'm on my way up there now", making it sound like someone from Oakville was on their way to Milton. The original call requesting the icall was on T/G 03-041 / 417 / 1a1h, a regular Oakville Transit group.
Reconfirmed today that the Milton buses are operating on the regular Oakville Transit T/G (417 decimal) on the Oakville EDACS frequencies, nothing logged on the north system at all. They don't talk very often, but the street names and other locations heard are definitely here in town.