Install Flash player without root privileges in Iceweasel (Firefox)

I need to install Flash player in Icewesel (Firefox), but I don't want to install it globally. I only want to use it in one of my several firefox profiles. This is similar to installing addons as a user in Firefox (inside the user's profile only). User can install any addon he wants and other users/profile on the same machine are not affected by that addon. I have downloaded the Flash player plugin from adobe.com and placed it in my plugins folder: ~/.mozilla/plugins/libflashplayer.so When I restart Firefox, nothing happens (I have expected the new plugin will be found upon start and activated). When I inspect ~/.mozilla/firefox/xxxxxxxx.default/pluginreg.dat, I see that a new entry has been added for the flashplayer plugin, but in the section [INVALID]: [INVALID] ~/.mozilla/plugins/libflashplayer.so:$ 1411257137000:$ I am sure this plugin version is compatible with my browser, because I was able to instal it on my test machine (using the standard installation method) **How can I install Flash player locally (in one user's profile only) without root privileges?** I am using Iceweasel (Firefox) 31.2.0 on Debian Wheezy (64-bit)