I've just updated to version "tomato-E4200USB-NVRAM60K-1.28.RT-N5x-MIPSR2-104-AIO" of the tomatousb firmware from a pretty old version and am very glad to see the pptp vpn server config now in the web gui.
I have been using the pptp vpn from a script for a while now, but when upgrading I noticed that my existing password would not work because it contains @#$ or one of those special characters.
I believe the fix is a pretty easy one, to allow all characters as passwords. In the '/tmp/pptpd/chap-secrets' file the password should be surrounded by quotes like so (as per man pppd):
chris * "@password#" *
If i manually edit the chap-secrets file, it works perfectly - would it be possible to fix the gui to add the quotes to the chaps secret file?