create rasterdataset without Spatial reference. (s.r. is defined) is it BUG?

Hi i create raster dataset (GRID) like this:

pRasterDataset = pWs.CreateRasterDataset(sRasterDatasetName, "GRID", origin, pRastProps.Width, pRastProps.Height, pRastProps.MeanCellSize.X, pRastProps.MeanCellSize.Y, 1, pRastProps.PixelType, pRastProps.SpatialReference, True)

and the result is raster dataset BUT whitout spatial reference. I take spatial reference from existing raster "pRastProps.SpatialReference" where is defined. When i debug pRastProps.SpatialReference has spatial reference (is not nothing)

Do anybody know where is problem? (AG 10.1, VS 2010, .NET 4). thanks a lot