Using Asterisk 220.127.116.11 + DAHDI 18.104.22.168, the FXS lines on my TDM840B get their FSK VMWI spill as expected. Testing * 22.214.171.124, same DAHDI, results in no FSK spill, only a line polarity reversal.
Stutter dialtone is correctly generated in both cases.
Is anybody running a similar setup with FSK MWI devices? Does it work for you?