Multiple servers to one tape backup

Hello,

   i seem to be having troubles when backin gup multiple servers to one tape, the result is that the first scheduled backup runs fine, and the rest scheduled for that night do not run, and i don't understand why.

i have my Media overwrite protection level set to partial. then within my jobs i have the first tape backup set to overwrite media, with a media set of 1 day for overwrite protection and append period.

this started because i used to have all the tape backups set to overwrite, and i would only have the last tape backup content on the tape. I just recently upgraded to BE2012 and its confusing me big time. Any help would be greatly appriciated. Thanks in advanced!