You can just reduce your hematoxlyin staining, to keep the counterstain from
overwhelming the DAB final product, an extremely short time or dilute the stain
to give enough contrast to see the chromogen endproduct and retain a delicate
morphology stain.  

We dilute Richard Allan hematoxylin 1, 1 part hematoxylin with 3 parts water,
and stain to desired intensity, since we found 1 dip was too much for some IHC
staining.  It only lasts for 1 day, then toss, since water dilution is not what
the hematoxylin likes, goes bad by the next day.  Their tech services was very
graciouson info about  this dilution method.  To test the stain, do a section
NOT IHC stained and optimize your counterstaining time before chancing bad
results with IHC stained slide with these decalcified bones.

OR try another counterstain.   

Gayle Callis