I put two line into extensions.conf exactly as you showed. these were using _5XXX & the other _6XXX
I did an astres.sh and tried the radio 5000 & 6000 no good.
Then I ran asterisk -vvvr and setup debug and verbose to level 9 keyed the radio I get a slew of node variable dumps for node 41470 8 variables and a hangup. Nothing in the debug showed the keys pressed on the radio.
MIke AE4ML