The only way to make it sound as if you are greedy to tell them the only reason you want them to be an EA is to improve your income.
While the buying of any goods by your affiliates is going to gain you commission the whole standpoint of SFI is duplication.
You can motivate your affiliates by explaining to them how they are going to increase both their status and financial position.
If you have a standing order for 1500VP or more and you have affiliates that want to progress then explaining to them how you do it is not being greedy. With the new badges your affiliates can see exactly how many VP your standing order is for.
The idea is explaining how the standing order is going to help them and not how it is helping you.
Your affiliates are going to have to do the same to their affiliates. If you want to progress then you need to have affiliates that are going to progress through EA to team leader. How ever they do this you are going to benefit even if it is only the extra VP from them attaining the rank that they reach.