.. what have I to do to get Shockwave Flash 11.2.202.394 installed and working?
Hello Eduardo!

Code:
aptitude update
aptitude install flashplugin-nonfree
After this have a look at "Iceweasel => Tools => Add-ons => Plugins"

On websites with Flash content use within Iceweasel the "NoScript" icon => "Temporarily allow all this page"