There's a bug in Drupal module Panels v2.0rc1a which you may need to keep an eye out for. If you happen to be using the default_panel_minis() hook to programmatically load minipanels you won’t be able to edit or export the minipanel once it has been loaded:

• http://drupal.org/node/329598

The only way I’ve found to work with the minipanel from that point is to paste the exact same code from the default_panel_minis() hook into the importer. A bit of a bug, you might say.

I haven’t tried any of the other default_panel hooks, but the minis one does at least exhibit this problem.

I'll post a follow-up if I find a fix someone else has committed or end up doing one myself.