post layout simulation

I'm sure you could have done something radical like reading the documentation - I don't know off the top of my head where this is covered, but it's searchable and I'm sure should be easy to find.

There have even been questions about this in these forums recently...

You have two choices. First a config view based approach:

1. Create a config view (File->New->Cellview and pick the tool as "hierarchy editor" - or type in "config" as the view name; it doesn't have to be called config, but that should fill in the defaults for you). Usually this would be created as a parallel view to your top level testbench schematic.
2. It will ask you to pick a template - eg "spectre"
3. Make sure the top level lib/cell/view is set to your schematic for the testbench
4. Do Right Mouse->View to use over the view used for the block for which you have created an extracted view with. QRC (or Assura RCX if using an old version)
5. Save.
6. Hit the Open button in the hierarchy editor - this will open your schematic, but it will show that it's using the config in the banner.
7. Launch->ADE L
8. ADE will show you that it is simulating with the config view.

The alternative approach is to bring up ADE and then Setup->Environment and change the switch list to include the name of the extracted view before schematic.

The config view approach has much more control and is more flexible, but the switch list approach is OK too. There are some things (like out-of-context probing) which assume you're using a config though.

Andrew