Problem saving style name and font name

I have made a regular and an italic font for the typeface named ‘OnzeFons’. In the Italic I have chosen te style name ‘Italic’ and added the Parameter ‘Postscript FontName’: OnzeFons-Italic. When I export an otf-file the italic and regular work nicely together. But when I close the ufo-file of the italic and open it again the style name is changed to ‘regular’ and the Postscript FontName is changed to ‘OnzeFons-Regular’. I tried over and over to change and save the style name to italic, but it is always changed back to regular when the ufo-file is reopend. How can I solve this problem?

UFOs can’t store all data that is in a .glyphs file. I’ll have a look at you use case if I can improve this.
But for now I suggest to save as a .glyphs file.

Thanks Georg. That solve dthe problem!