What do you mean by "The Audigy supports audio only"?

It does support midi and it does support soundfonts, look at the specs:

SPECIFICATIONS
Technical Specifications

Channel Signal-to-Noise Ratio (A-Weighted)
Front/Rear/Centre/Sub 102dB @ 2Vrms
Headphone/Side 96dB @ 2Vrms


24-bit/96kHz Analog-to-Digital Converter (ADC) for various analog inputs
24-bit/96kHz Digital-to-Analog Converter (DAC) for up to 7.1 channels output
Supports Sony/Philips Digital Interface (S/PDIF) format input signal of up to 24-bit/96kHz quality
Recording/Playback: up to 24-bit/96kHz*
SoundFont 2.1 Support for Midi playback

Connections and Controls
USB connector
Line In
Mic In
Optical S/PDIF In
Line Out (Front/Rear/Center/Sub)
Line/Headphone Out (Side)
Optical and Coaxial S/PDIF Out
Controls:
- Master Volume Control
- Mic Volume Control

Indicators:
- Power LED - Dolby LED
- Mute LED - CMSS LED
- IR LED

However the Extigy does NOT support soundfonts.

(see here: http://www.soundblaster.com/products/audigy2NX/compare.asp )

Hope this helps,

Greetz ,
Marcel