adding ids and df to hexagonal polys ?

Hi, 

I am trying to understand the different data types in the sp package.
However, I do not seem to get the way that spdf are built. 

For example, let say that I can build a hexagonal grid. That work just
fine using

regio <- readShapePoly("regions.shp")
hpts <- spsample(regio,type="hexagonal",cells=30000)
hpoly = HexPoints2SpatialPolygons(hpts)

I'm unclear about adding a df with IDs to this new SpetialPolygons class

I guess that I'm not understanding how ids are assigned... any hint
would be appreciated

thanks