Addressing the session node from Mu

Sorry if this is a dumb newbie questions, but is there a way to address the session object in Mu?

Every RV session file seems to start with an RVSession object, but I can't find a way to address it in Mu code.  That is, although at the top of the session file you have something like

rv : RVSession (2)
{
    session
    {
        string viewNode = "defaultStack"
        int marks = [ ]
        int[2] range = [ [ 1 25 ] ]
        int[2] region = [ [ 1 25 ] ]
        float fps = 24
        int realtime = 0
        ...
    }
}

...even so, in Mu code,  I can't seem to find a way to address that object.  Both the name-oriented form

    propertyExists("rv.session.realtime")

and the class form

    propertyExists("#RVSession.session.realtime")

always return false.  Is there something really obviously I'm just missing?

The reason I'm asking is actually because I want to put custom attributes on the session; we're sending some data along to the RV session for Mu to handle later, and the information is really global to the session so it would make the most sense to put it on the session node.  If that's impossible we'll find somewhere else to stick it in, I just thought I'd see if I'm doing something wrong.

Leo