Hmmm, at first I wasn't so sure. On older Ravens, that's just been a normal 120mm fan slot. But after browsing the extra pictures on Silverstone's site, that vent is labeled an independent PSU intake, so there you have it. So out of curiosity I took a picture from SS' site and my RV03 and worked a little mockup.
After scaling the mboard and PSU appropriately ( using the AP-181 in each case as reference, ) and lining the mboard up with the standoff holes in the RV05, you'd get something like this ( I know the PSU would be rotated with the exhaust up, but it's the same thickness in the picture. )
It's tight spacing between the mboard and PSU, but it works ( I think the PSU might even fit further back, making a more comfortable gap. )