There are 2 constraints:
1)the application manager uses dpkg backend which is using default setting: install to /
2)linux virtual file system can block the execution of some binaries if the partition is mounted "noexec". This is to prevent that someone puts a usbkey containing harmful binaries.

It's been recently talked here

1)
* You can bypass application manager and execute dpkg to install it somewhere else (see above link)
* You can modify dpkg default settings to always install to /path. I don't know what's happening in case of updates where one software is installed on / and you ask to upgrade it to /path ..
2)
* To check if your destination directory is allowed to execute binaries, use /bin/mount
* If it displays noexec then you will need to remount the partition with correct option.
mount /dev/device /mountpoint -o remount,defaults <-- not 100% about the syntax.