Loading Diffusion datasets with DCMTK (Siemens private b-value tag):  

VM (value multiplicity) in DCMTK for the VR="OB" is always set to 1, while

it needs to be variable.  This affects the private Siemens tag for B-value

so only the first character is read (i.e.  "4" instead of "400"). 

 provided a general workaround for VR = {OB,UN}