So, to repeat:
If you do have an Electron card that does not have that restriction on the rear of the card I'd be interested to know which bank issued it.
If you do have that restriction then bear in mind that it may have been accepted by mistake in the past but that you are NOT MEANT to use that card for cardholder-not-present transactions. Both you AND the retailer are violating your respective agreements otherwise. So please stop doing it.
Obviously though you have managed to use it over the net, so where it says must be swiped this must be in theory rather than in practise.