I presume you are talking about using the FF7PSF from the Soundfont project? (I`m using that anyhow). Looping of MP3s is broken in FF7Music.
The readme that accompanied the file explains this. But sure:
Open FF7music. Go to the setup tab. Make sure you`ve selected an input plugin (inf_psf.dll?). Go to configure for the input plugin. Check the "force all songs to play indefinetely". Should work