MWI notifcation on analog phones

As I understand, the message waiting indicator on analog phones when sitting behind an analog FXS gateway (ie: Mediatrix), will only work if the phone has FSK built into phone chipset. Otherwise, only stutter-dialtone will work. Is this true? Alternatively, I know that I can buy a channel bank and will not have any problem. However, channel banks are more expensive. Can someone please tell me if they were able to turn on the MWI light using an analog phone without FSK with a FXS gateway.