MOSCOW, Dec 7 - Mobile TeleSystems (MTS) * Announces it has entered into a credit facility agreement in the amount of up to $165 mln backed by Export Development Canada * Says will use the facility to finance advance payments to its vendors within a 12-month period from the date of the signing * The facility matures in Dec. 2012 and pay an interest of 6-month LIBOR LIBO plus 4.5 percent?