AEP's holding in IBA is204.4m shares1.28 m warrants which...

AEP's holding in IBA is
204.4m shares
1.28 m warrants which convert 1:1 into shares
45.97 conv. notes which can convert into 1.157 shares for each note. Thus if they convert into shares they could own 258.9 m shares. Given AEP has 91.9 million shares on issue, thus there is exposure to 2.82 IBA shares for every 1 AEP share. This is a little more than your calc which may be due to the buy back and cancellation of AEP shares.

Also worth noting the loan to IBA now $60m AUD is due 30 June 2009, be interesting to see if they can afford to repay on this date, also makes a wind up of AEP easier.