With Westpac Altitude you book flights directly from the Altitudes web site or by selecting the "Redeem my points" option on the right hand side of the Westpac online banking site once you have signed in
The Altitude web site welcome screen presents a panel labelled "Altitude Travel" on the right hand side. Use this panel to select your travel dates, whether you want domestic or international travel, number of passengers, fare class etc and select search. For domestic travel you'll be presented with a list of flight options from QF, JQ and DJ.
Select the QF flights you want and select "Book Flight". You will now be presented with the fare conditions for each flight, plus a breakdown of the total points required to "pay" for the flights, taxes etc. From here you can then proceed to enter passenger details etc and continue with the purchase, or back out and perform another search or whatever.
My understanding from discussions with Westpac is that the Qantas fares booked in this manner receive SCs and FF points commensurate with the class of travel booked.
Good luck!
Mongo