Problem with colour profiling in Distiller & Acrobat

I have a design made up in Freehand(MX) with a photoshopCS tiff, the photoshopCs tiff has a black background and on one side i have a black background created in freehand using 100% black. Now the problem i am having is that when i print the postscript and distill in Distiller, everything goes fine with no errors. But when i open the PDF in Acrobat the black created in freehand shows as a faded black(GREY) unlike the black from the tiff which shows as normal, even when i print it prints as shown on screen. I had sent it to a repro house and was told that the entire PDF is in RGB which was set as CMYK initially. Please help someone, i am totally clueless spending days & nights tryin to sort my problem out.