IBufferConstruction unionoverlappingbuffers not working

.Net Framework 3.5, windows xp, ArcGIS 10.1

I am trying to use IBufferConstructionProperties and the method unionoverlappingbuffers to union/dissolve multiple geometries that i have in a geometrybag. And i project the geometrybag to Albers Equal Area projection before adding the geometries to geometrybag. So when I construct the buffer the output geometry count is always 0. But if I don't set the unionoverlappingbuffers to true then the out put geometries are returned in same number as the input geometries which is fine. I am not able to find out why the count is 0 when i set unionoverlappingbuffers to true. Is there a example how to use it. Or any ideas what I might be doing wrong.

IBufferConstruction bc = new BufferConstructionClass();
IBufferConstructionProperties2 bcProp = bc as IBufferConstructionProperties2;
bcProp.UnionOverlappingBuffers = true;
bc.ConstructBuffers(enumGeom, bufferdistance, outPutGeom);