In reply to elliot.baker:
Mount your item to a wooden/metal plate, then mount the plate to the wall if the item has a small fixing area. I think your bar has enough size and fixing opportunities to spread the load, but you need to use special fixings rather than screws - although your static weight isn't excessive, your dynamic load can exceed 2.5kn (eg. bounce testing can break small RPs) Aerated thermal blocks require special fixings - googling 'heavy duty fixings for aerated blocks' yields some useful results.
This is useful:-
http://www.fischer.co.uk/PortalData/10/Resources/support/sales-documents/do...
The resin mortar option is the one you need. Better to be overkill than blow out a block (or more).
Can you put threaded rods right through the wall with a backing plate on the far side??
Post edited at 12:16