Ok, you mount the .bin-file with DaemonTools? Now see that letter assigned to the .bin-file as a drive letter? Mount it in DosBox as a CD-drive. For example, it's a letter
g:
mount d g:/ -t cdrom
mount c c:/anydirectory (create a directory there to install X-Wing to it)
d:
install.exe (or similar to install the game, you need to install it first, right?)
There choose simply the
c: as the installation directory. Then:
c:
install.exe (if you didn't setup the sound / music after the installation, which actually should come up automatically)
xwing.exe (or whatever starts the game)
I hope this one helps you, if it doesn't, ask here again, we'll see if we can help more.