I am not sure if you guys have worked with 9.3.1 and successfully created editable features, if not here are the instructions on successfully creating editable feature classes and should also work with a mobilecache.
1) Have a shapefile or many shapefiles that you want to use.
2) Right click on your database connection > Import > Single or Multiple (if they have same spatial reference)
Single > Browse for the Shapefile > Give a name for output Feature Class
Multiuple > Select all the Shapefiles > Then hit Ok (no need for naming, the geodatabse will take the shapefile names, unless the feature class/feature dataset already exists you will get an error because of the name).
3) Once your FeatureClass or Dataset set is imported into the geodatabase you can then modify the featureclass as you like.
For example, click on the feature class > Preview > Table > Add Field > Name: Photo > Data Type: Raster or Blob. <- This is for adding a photo field, so you can add images to what you collect.
4) Then right click on the Feature Class or Data set and click on Add Global IDs, this will make your feature class editable.
5) Configure your domains and Subtypes.
6) Register as Versioned (might be optional)
I just figured out today that if I don't Register as Versioned, the FeatureClass in ArcMap is more editable, meaning I can use Field Calculator and Calculate Geometry. Yet my featureclass is still properly versioned in ArcMap. Interesting! ;).
But if you do register as versioned you will lose the abilities mentione above.
Then proceed with creating your project in Mobile Project Center.
Forgot to mention, you can still create a Mobile MapCache and these layers should also be editible when you properly configure it in Mobile Project Center (when you add Mobile Cache Data).
Let me know if you have any problems.
