Apple's Numbers format

Is there any class out there that will create a Numbers formatted file?

I have created a set of classes for Excel but wish to support the Mac also and export a file in the Numbers format.

Good luck.
Latest version produces folders with xml files (zipped)

I forgot the answer: There is as far as I know no class available.

But Numbers can read excel files…

No, the latest version is a zipped folder with protocol buffer files. And AFAIK there is no documentation of these “proto”.
So for now is an ultra closed file format.

Since you can write Excel files use that format

Thank you everybody for your replies.

I cannot use the Excel files that I produce as these are the 2004 XML structures that loads in to Numbers as a text file displaying the XML lines. These are great for Excel and the results are great but I was looking to reproduce a working Numbers file.

I don’t like CSV as there are no formatting controls available and this is not really an acceptable solution.

Oh well, I guess I cannot have what I want.