Steps to get the Tascam FireOne working with Vegas Pro 8.

Install the FireOne drivers from CDROM.  There are two driver
installs that will run back to back,
first the Null driver, then the actual audio and MIDI drivers.
Start the installer BEFORE you connect the FireOne to the computer.
Watch the installer prompts, it will tell you when to connect
the FireOne and power it on.

When driver install is finished, Restart the computer.
Launch Vegas Pro 8.

Go to "Options" on the File menu, click "Preferences".
Select the MIDI tab.  Check the boxes for FireOne MIDI and
FireOne Control on both the Output
and Input sections. Click "OK". This will return you to the
"Preferences" window.
Select the "External Control & Automation" tab.
Under "Available Devices", select "Mackie Control".  Click Add.
Under "Active Control Devices:" right click, a menu will pop up, click "configure".
In the new window, under "Device Type" select "Emulated Mackie Control Device - 1".
Under MIDI input, select "FireOne Control"
Under MIDI output, select "FireOne Control"
At the bottom of the window click "OK".

This will return you to the "Preferences" window, click the "Audio Device" tab.
Under "Audio Device Type" select "Tascam FireOne".
Click "Apply", then "OK".

This will return you to the "Preferences" window, click Apply,
then "OK".

Click "Options" on the File menu.
Go down to "External Control" and click, a check mark will
appear.

The FireOne transport controls, jog wheel, and audio IO will
now function in Vegas.