I am pretty sure it has to come from an external account. But it's really easy.
Option 1. Check to see if your pay can be paid into multiple accounts, and have ~$250 per week paid into an ING account. The cash doesn't have to stay there, you can spend it, or move it to your usual account the same day.
Option 2. Do a transfer from any external account you have of $250 a week. Then transfer it back again the same day.
(I'm not sure that ING would approve of option 2. But still, it's worth thinking about.)
I actually went and got two accounts with ING for a few reasons, one of which was this 4%. I'm getting half my salary paid into the Everyday account, and half into my other account. One of the key things with ING, is that it's free to have the account, it's free to transfer money (makes it easy to pay bills) and if you do pay $1000 into it every month, it's free to use ATMs as well. I don't know why people still have everyday accounts with places that charge them $5 a month to look after their money.
And, if you do transfer money from the savings maximiser, you don't lose the 4%! So I actually leave my cash in that account most of the time, and then when I do need to pay a bill, just transfer the amount needed to the Everyday account, and then the next day pay the bill. (And this can be setup automagically.) It might only be a few cents a day (amount-in-account times 4% divided by 365 equals amount-of-interest-per-day), but it all adds up.