I thought the Tascam could emulate the Mackie Control ? If so I doubt Sony will support the Tascam's native mode as it is already supported via the Mackie emulation.
Unfortunately, the US-2400 is discontinued and Tascam is out of stock. This means that it is not a viable development project for us to support the US-2400 natively in Vegas (or ACID) as we would need hardware from Tascam to properly implement support.
The US-2400 does emulate the Mackie Control Universal and both Vegas and ACID work with this device. However, there is a limitation of only accessing the first 8 channels on the US-2400. Again, with out a unit from Tascam to develope with, we cannot realistically support the emulation mode of all 24 channel faders.