The Ansmann R3.1 is basically a re-badged Sanwa RX-371, I have 2 R3.1s which work quite happily with my MT-4 in the FH2 setting (although Sanwa say it uses DSSS1):
http://sanwa-denshi.com/rc/car/receiver/rx-371.html
Where it gets confusing is on the TM-221DS webpage they say it's compatible with the RX-371:
http://sanwa-denshi.com/rc/car/speed.../tm-221ds.html
But on the receiver compatibility table they say it doesn't work in combo with the M11 and RX-371:
http://sanwa-denshi.com/rc/common/pdf/tx_rx_conform.pdf
I personally would give it a try, probably the worst that can happen is they just won't recognise each other
