Try calling Neve NY. The LA office doesn't seem to be able to get very much accomplished lately. The brand should be Vishay, style PA11.
http://www.vishay.com/docs/51031/p11.pdf
Good luck finding anybody who stocks the combinations you'll need though. Neve is probably your best bet.
Which V Series do you need them for? They may be different on the different incarnations, most particularly whether or not it was built to have recall, which takes an extra gang. Check and see if, in your manual, ahead of the schematics, there is a parts list. If so, it should have the correct numbers for them. Sometimes they are listed as "PT#####" rather than the "RV#####" one might expect from the nomenclature on the schemo.
The "A" you see is Sfernice's(original mfr, bought by vishay) code for
linear taper, as opposed to seeing an "A" and thinking audio. Finding anybody who stocks center detent might be trouble. You could give Farnell a try, But I'd still say your best bet is Neve NY. They are current production, so if you want a boatload, Vishay might put together a batch for you.