/var/etc/wpa_supplicant/satellites.xml and /var/etc/tuxbox/scce/satellites.xml
these locations are wrong full stop, you seem to be getting to these locations via symlinks.
/var/etc/wpa_supplicant/ should just be /etc/wpa_supplicant, it does not contain any satellites.xml on my boxes running vix.
/var/etc/tuxbox/scce/ should just be /etc/tuxbox/scce/ and does not contain any satellites.xml on my boxes running vix.
/etc/tuxbox/ does contain the file as Abu said, he also told you where to put the file.
TBH if you have done a clean install of vix you should not need a fresh satellites.xml file to recieve extra channels from 28.2, if you are having tuning difficultys it most likley your a problem with your dish/lnb or cables.