

Yeah that is different than the ext plugin so there would be no Advanced button. The delete button should be all the way to the right...not aware of any bugs about this. If it is absolutely not there, maybe try a different browser to access Jenkins?
Otherwise, you should be able to go into the folder for the job on your server, edit the config.xml and take the mailer task section out of the job:
<hudson.tasks.Mailer plugin="mailer@1.4">
<recipients>some...@email.com</recipients>
<dontNotifyEveryUnstableBuild>false</dontNotifyEveryUnstableBuild>
<sendToIndividuals>false</sendToIndividuals>
</hudson.tasks.Mailer>
This section is under the "publishers" section. Then I believe you have to go to "Manage Jenkins" and "Reload Configuration from Disk"