Well it looks like it would let you do it on the screen, but I never actually tried it. I just thought I remember somebody saying that had done it (paying for ecerts with ecerts).
Anyway, I got points for 6 different Tupperware offers since last Thursday. I actually did a 7th, but my internet connection went flaky when the order confirmation screen was trying to come up, so I never got to click on the link to get the points. But of course the order went through, so now I just have to wait to send them an email to get those points.
But on another note, the points I was waiting for for an Overstocks.com order I placed in December seems to have been added to my account. I had to email them and ask about them. I thought it was supposed to be 300 points. But when I checked this morning there was 400 points added to my account!
Yippee! I have over 10700 points, so I'm off to cash out for some Webbies. My first webbies! I've cashed out for other things before, but not web certs. I know that Barnes&Noble is still the best points/dollar redemption (110/$ vs. 140/$ for webbies), but I now like the idea of being able to get Disney Dollars. DS only needs so many books! Well, okay, you can never have too many books, but my goal is now Disney Dollars. And since I plan to get more in the future, I'll probably just order the plastic card rather than going through the hassel of hoping they'll take my printout.