The storage provider was never loaded in our case. So I had a look at the method
void QmitkStoreSCPLauncher::FindPathToStoreSCP().
The appPath is fetched but never used.
Should it be
m_PathToStoreSCP = appPath + fileName;
instead of
m_PathToStoreSCP = fileName;
in line 68?
Changing it in this manner makes the storage provider work for us.