If E-Health has those little cartridge inserts, then I should definitely mention one other thing...I never had any luck at all refilling the e-health cartridge inserts. I use that unit exclusively for dripping (dipping, really) now, mostly when trying a new flavor. And even if you could, they honestly hold little more liquid than you'd get from dripping. Those inserts are tiny.
If you are going to refill them, you need to pop those little inserts up out of the cartridge.
If you are trying to refill them by dripping juice down into the cartridge you will definitely get lots of juice down the sides.
The little inserts pop out really easily though, just push a straightened paper clip up through the hole in the mouthpiece.
But yeah, seriously, those little cartridge inserts hold so little juice you are far better off just dripping.