Is it posible to create a vba/macro using Open Xml Format and open xlsm files

Hi,

We're trying to use the Open Xml Format Library for generating excel documents. So we would like some infomation and specifications about Open Xml Format.

What we want to do, is to write the vba Macro statically from c#, and then add them to an excel document without using interop.

And a second thing we are wondering about is, whether it is even posible to open a .xlsm in Open Xml Format?

Hope you can help with these questions.

Best Regards

Joakim