Fitting this fan?

[Trebby]

Hey guys,
I've just bought myself everything for a new computer, and I've built numerous ones before, but I'm kinda stumped, and rather than risk damaging it all I thought I'd ask here:

I've gone for the 939 option - an Asus A8V, Winchester 3200 OEM and one of these Arctic cooling heatink/fans, as mentioned in the title. I've never seen a fitting like this for a heatsink before. Basically, on each side of the fan there are 2 screws, which seem to line up with the ones on the motherboard holding the retention bracket in place. I expected there to be clips on the heatsink, and then these would attach to the retention bracket thingy, but there aren't. No other retention bracket was included with the heatsink. Picture of heatsink/fan:
Pic of heatsink

Do I remove the retention bracket from the motherboard completely and just screw the heatsink in like that? It seems a little... odd? Almost as though it's putting too much pressure on the CPU?
I don't know, maybe I'm being stupid

Anyway, I'd appreciate some detailed instructions from someone, if they'd be good enough to spare the time.

Thanks.

 

[duffers20]

i'm not 100% sure about this, but if the heatsink needs to be screwed to teh motherboard, then there should be a backing plate on teh mobo to support it, but i guess it really depends on the weight of the headsink. hopefully someone else can give there advice.

 

[Trebby]

Thanks for replying.

Well that's what I thought - it seems odd to fit a fam directly to the motherboard without a backing plate or anything. It does say on the Arctic cooling site that it's a low weight heatsink, but even so...? Anyone else got any ideas?
Thanks.