hi, Gio_it, actually I've never used that stuff (Excel 2010) but try the following:
1. Open Excel 2010
2. Open your file in Excel 97-2003 with macro inside in Excel 2010.
3. Save the file in Excel 2010 format (I suppose it should be sort of .xlsm or whatever type with macros enabled)
4. Repeat your steps on creating button and assigning macro and check it out