As noted in the documentation and in the readme files, Rasters (Raster Dataset, Raster Catalog, Mosaic Datasets and Raster Attributes) are not supported with the initial release of the File Geodatabase API. This did not change in the 1.1 release. It may change in a future release.If you want a list of mosaic datasets the call is:geodatabase.GetChildDatasets(L"\\", L"Mosaic Dataset", childList)
The code you used returns a list of all child datasets. This includes the mosaic datasets and all of the hidden feature classes that are associated with them. These hidden feature classes can be opened and read, but the contents are not documented. We block inserts and updates to these files to avoid unintended corruption.geodatabase.GetChildDatasets(L""\\",L"", childList)