Volume controls for OSX when using external soundcard

"Brilliant with Soundflower, it works perfectly. For the beginner, follow the following steps if you want your volume keys to control your volume in OSX while your are using an external soundcard (USB, Firewire...):
- Install Soundflower > Look for the website Cycling74.com
- Open Preferences in OSX
- In output, select Soundflower 2ch or 16ch (it means that your signal from iTunes or more generally from your OSX applications will go to the virtual inputs of Soundflower
- Open Soundflower > A flower will appear on the top right corner of OSX
- Select your soundcard in Soundflower 2ch (just below, your soundcard should appear)
- Make sure the outputs in Soundflower are rooted correctly

Then, it will work !
It you want this to work permanently, make sure Soundfower is launched each time you start your mac. For that, go to Preferences, Account, Login Items and add Soundflower...

That`s it. Good luck,
Note: adding simple comments on Internet could save some time for lots of people... this people might you one day !"

"Just been through the same loop as you. I haven't yet made up my mind whether to go with this software solution or change to a external interface with volume knob, but what you want is possible.

Download Soundflower, a virtual audio bus for routing audio inside OSX. Set your system's sound output to Soundflower's 2-channel bus. The OSX volume controls work on this bus. You can then send this bus to your external soundcard using the menuling. In my case, I also turned down the individual channel levels for the Soundflower bus so I get a volume range a bit friendlier to sitting right in front of the monitors (via Audio MIDI Setup).

http://code.google.com/p/soundflower/"