Hi Harald,
There were a change on iOS recently what made this method unavailable but we will provide a solution to make URLs in Legacy info type work again with the next update. It will be released within a few days.
Although on longer term I suggest you to use the recommended new way of custom element info and URL distribution with BIMx Hyper-model. See in details here:
http://helpcenter.graphisoft.com/tips/bimx/custom-info/
Regards,
Gyuri