Comment 13 for bug 457123

If there are other people with this problem who needs it fixed, you can install from source pretty easily:

sudo apt-get install build-essential automake autoconf libtool pkg-config libcurl4-openssl-dev intltool libxml2-dev libgtk2.0-dev libnotify-dev libglib2.0-dev

wget http://download.m0k.org/transmission/files/transmission-1.80b3.tar.bz2
tar xf transmission-*
cd transmission-*
./configure --prefix=/usr -q
make -s
sudo make install

This will overwrite Transmission 1.75 with 1.80b3 and I can confirm suspend now is prevented.