[XXE] Restriction with CSS

[Tahia]

Hello,

the element "background-image" seems not to be supported.
Is that correct?
If it is the case, it will be very useful to mentionne it on the
officiel documents.
It is not the case at Power's user guide $6. CSS2 support.
Is there a complete list where we can find the unsupported properties of
css?

Thanks,

        Tahia