Effective DCFDA Protocol for Non-Adherent THP-1 Cells? - (May/09/2011 )

Does anyone have a working CM-H2DCFDA protocol that can be used with non-adherent THP-1 cells? We use the CM-H2DCFDA kit from Invitrogen and have never had a problem staining lung A549 or H292 cells, or caridac H9c2 cells. I've tried modifying our usual protocol in different ways but nothing I've found online or in articles is doing the trick. Any advice guys?

Or, you know, if anyone has any tips regarding the use of this assay?

C'mon guys.