Tvheadend

Hi,
I'm currently using TVheadend 3.5.247 on my Linux Mint Debian Edition machine.
My goal is that after every record I get an e-mail that the recording was successful. The shell-script works very well and does what it should do but it isn't executed when a record has finished.
My post-processing command is: /home/hts/sendemail/sendemail.sh -s "%t" -c "%c" -p "%f" -d "%d" >> /home/hts/sendemail/tvh.log &
My program has been recorded (.ts file is well created and it's recorded without any problems) but there is no e-mail and I get nothing inside my tvh.log file. But if I start this shell-script in a terminal with "su hts", so from the user hts, it works just fine and I get an e-mail notification.

What did I do wrong in the post-processing command and how can I make this script working well with TVheadend?
I hope you can help me!

Sven