I can't seems to get avidemo to work . I've done perfectly as this post instruct me .

But each time I run the game , my config_mp.cfg seems to delete the commands I added which is
- bind F6 exec "avi_on"
- and bind F7 exec "avi_off"

all of'em I've set to CFG format , used Wordpad instead of Notepad but my binds keeps missing each time I started the game .
I've tried set "read only" on the config file but it still doesn't works .Help ??