Text hidden inside 3dm-file

I want to save text and numbers made from a form inside Rhino in the 3dm-file.
The only way the user should be allowed to change this text is via my form.
How can I save text and number inside a Rhino file?

Use the plug-in’s ReadDocument and WriteDocument methods and override them with your implementation. This way you can save and restore any user data.

http://developer.rhino3d.com/api/RhinoCommonWin/html/M_Rhino_PlugIns_PlugIn_ReadDocument.htm
http://developer.rhino3d.com/api/RhinoCommonWin/html/M_Rhino_PlugIns_PlugIn_WriteDocument.htm

Thank you!
My problem is solved!