You have two options to do this:
1. Export ALL parameters of used library parts via IFC Translators tab 'Export Options>Derived Model Data to Export>All Library Part parameters as custom IFC properties' ... not recommended though as you will get a LOT of stuff you dont need or want.
2. File>File Special>IFC 2x3>IFC Options and in there you can configure a mapping file with only the desired parameters for export. Instructions are in the AC Help (search 'IFC Options'). Obviously the recommended way, but takes a little time to configure properly.
Just a note of interest - parameters which are hidden from the user in the interface are not available for export through the 2nd mapping method, although the 1st method does export them.
hth
owen
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5