You can't actually simulate those events, to my knowledge, as SINE (Scratchbox Is Not an Emulator (TM)), however, you may be able to use D-Bus in some cases to simulate some of the effects of various events. I'm not actually sure, but you might want to look into it.

You have to add some lines to /etc/apt/sources.list in sbox. Look in /etc/apt/sources.list.d/hildon-application-manager.list on-device for examples. Note that lines beginning with "deb" are binary repos, and those beginning with "deb-src" are the corresponding source repos (where they exist - accessible using apt-get source) - otherwise, the syntax is identical.