Assuming that your image is created correctly ( data & audio tracks present ) are you sure you're doing the imgmount to the .CUE file? Because if you do it to the .BIN then no audio track is played...

Yes, i'm mounting the CUE.

OK, in the meanwhile i tried mounting the CD in DOSBox in every way i could think of. I tried the "usecd" and "ioctl" parameters, the "mount" command with the image mounted in Daemon Tools and with the original CD, and the "imgmount" command on the CUE. Just to be sure, i started Dungeon Keeper, which also has CDDA, and the audio tracks worked. Anyone?!

but i can't select CD-Audio in the ingame setup

What does that mean? Should it be selectable? Or maybe it
detects cdda at game startup?

I think both. When the game is starting, it says "Extreme Assault CD found in drive e:" (i have c: and d: mounted as hd's). In the game, there is a "sound setup" menu. Only two options are selectable: "MIDI" and "No music". I assume there should be a "CD-Audio" option, but i'm not sure about that.

Edit: I did some more testing, and tried to run the game under XP with the VDMSound/DGvoodoo combo. CD-Audio still won't work. Without using SAPUCDEX, the game won't even recognize the CD.

You might want to try to debug the game.
Set a breakpoint on int 2f call 15

Ehm... You got me there. I have no idea how to debug inside DOSBox. I presume i'd need a debug enabled DOSBox build, right? If there's any documentation available on the debugger, i could try to do it. But i think i don't have enough knowledge about DOS coding (or coding at all) to be really helpful with debugging...

Necroposting in my own thread! Man, a lot of stuff has happened since this thread started. Anyway, CD-Audio in Extreme Assault works great in DOSBox 0.74. I think the game has to be installed with the "recommended" install setting. Music can then be switched to "CD Audio" from "MIDI" in the game options menu.