Create a master volume control in .asoundrc

[cogadh]

So I've decided to revisit an old problem of mine, the lack of a master volume control in ALSA with my Audigy LS. I have already used a custom .asoundrc to make all of my 5.1 speakers work, but I have to control the volume through three separate controls (Analog Front, Analog Rear and Analog Center/LFE). I would like to be able to have a single volume control that adjusts the volume as a whole, while retaining the ability to fine tune the volume with the individual controls I already have. Here's the current contents of my .asoundrc:

pcm.!default {
    type plug
    slave.pcm "surround51"
    slave.channels 6
    ttable.0.0 1
    ttable.1.1 1
    ttable.0.2 1
    ttable.1.3 1
    ttable.0.4 0.5
    ttable.1.4 0.5
    ttable.0.5 0.5
    ttable.1.5 0.5
}

What do I need to add to create a working master volume control?

Also, since upgrading to Kubuntu 8.04 (finally successfully did it this weekend), I've noticed that the volume I set on the Analog Rear and Center/LFE controls using the Kmix applet does not "stick" with a reboot. If I use alsamixer to set the volume and then do "sudo alsactl store", it also doesn't retain the volume settings for those channels. Any ideas on that one?

EDIT - I fixed the volume not "sticking" problem. Apparently, using the Kmix applet instead of Kmix from the Multimedia menu was the problem. Once I switched to the menu version, everything was fine. Still need help with the master volume control, though. I've gone through all the ALSA documentation on this subject and it is... confusing, at best (like most of ALSA's documentation).