Unfortunately, the Metacello configuration has been created and used only by Pharo-centric users until now...
You could eventually correct the Squeak branch in the configuration, but that ain't going to be easy to boot up from there.
If you are interested in oscog VM branch, then there is one prebuilt 4.3 image with pre-loaded packages distributed in this svn repository
http://squeakvm.org/svn/squeak/branches/Cog
Look under image subdirectory, open the CogTrunk43.image, there is a workspace explaining how the packages were loaded in the image.
If you are interested in classical Interpreter, then the way to load it was by using the update MCM:
- Open a Monticello browser
- Add the VMMaker repository
(MCHttpRepository location: 'http://source.squeak.org/trunk' user: 'squeak' password: 'squeak')
- Select and open the VMMaker repository
- On the left pane, select 'update' (bottom item)
- On the right pane select the top item (update-dtl.12.mcm)
- Select 'browse' button
- You get a list of packages displayed, click on 'Install' button
The update configuration is a few versions late though, not sure if it is still maintained, the best is also to ask on "Squeak Virtual Machine Development Discussion"
EDIT I think that this magical incantation can replace all GUI oriented operations above:
MCMcmUpdater updateFromRepositories: {'http://source.squeak.org/VMMaker'}.