here in the uk you need to text the word 'on' to 'phone number' 212.

maybe e-plus has a similar requirement?

I found nothing about this on the eplus-website.
But the SMS-function from the google-calendar works fine. Is there any difference?

Not sure. You maybe need to speak to eplus.

there is nothing on the o2 uk website either - but if you call them, and get someone who has a clue, then they will say you need to text 'ON' to 212. You can switch it off my texting 'OFF' to the same number.

I don't use the SMS function as o2 charge me to receive this kind of text and do not take it from my included txt bundle.

Hi stephan,

the big difference is that Google uses its own SMS Gateway, while we are dependent on the SMS Gateway of your telecom company (we send an email to them which they convert into an SMS)

Would you be able to submit a support request through email? We will then be able to collect all relevant information;
http://www.rememberthemilk.com/help/contact/support/?ctx=reminders.newissue&report=1

so, e-plus told me, that i really need to open this service manually.
If anybody has the same problem:
Send "start" to 7676245, it coasts 25 cent per sms.
(You can stop it by sending "stop").