I'm joining our university's chamber choir for a trip to Rome next month. Among our performances will be singing for Mass at St. Peter's Basilica. I'm very excited, of course. (I'd be more excited if it weren't for the fact that I'm just so darn busy at work right now!)

The Mass will be on a Monday evening, during Lent. Our literature includes Bruckner's Locus Iste (I'll be guest-conducting this, as an "opening" piece — I'm guessing in place of the Introit?), plus Palestrina's Sicut Cervus, a wonderful setting of Ubi Caritas composed by one of our undergraduates, and Terry Schlenker's Timor et Tremor (perhaps a bit more of a "concert" piece, but still very beautiful). Aside from the Bruckner, I'm not sure just when we'll be singing each piece during the Mass (i.e., which one for Offertory, Communion, etc.). Granted, they're not the propers, but they're still very beautiful pieces. (I'm very grateful to our excellent conductor of this choir — not Catholic — for giving me this opportunity.)

I'm not quite sure what to expect regarding the Ordinary. If any of you have been there — particularly for a weekday Mass — does the "Musical Chapel of the Papal Basilica" sing, in alternation with guest choirs? Would they sing Mass XVIII? (The good ol' "Vatican Norms" document doesn't indicate anything for weekday Masses.) Would they sing a Credo? (Could we sing along for any of that?) Would they sing any of the Gregorian propers?

Any insights would be appreciated!