Morning glory and setting seed

[cereus]

I have been having problems when growing the morning glory plant this year; it simply fails to make seeds, lots of flowers but no seeds. I live in Norway and the cold spring weather this year killed my first plants, but the next batch thrived and produced lots of beautiful flowers.
Why no seeds, I even tried to pollinate the flowers, as I have had success with other plants that seems to lack a pollinator, but with no success.
Any body know why I am having this problem?
I also read about it in an old book on plants in my area and it was there referred to as being infertile or sterile in my area but with no explanation to why it.

[llamabox]

Is it a double peteled version. Meaning 2 rings of petals.
These are infertile and self-incompatible doubles where the stigma/anthers turn into infertile petals.

[cereus]

No I think it is a regular morning glory. I planted seeds from two different origins they seem like but one was labels as violata, and one as heavenly blue.
The book I refer to is lids flora and he mentions the ipomoea as a stray plant that sometimes sprouts from discarded ballast of boats from southern America. It is an old book but regarded as a milestone in modern botanical classification.