Here are extracts fromWavepad help.
With the Master's Edition you have a set a features designed with the professional in mind. These include a file batch converter, keyboard macros and automation tools, bookmarks, file regions (with the region assembler) additional file formats and more.
Features ~Supports a number of file formats including wav (multiple codecs), mp3, vox, gsm, real audio and more.
Save an audio file
To save the current audio file with the current name press Command+S.
To save the file with a different name or in a different format use the menu File -> Save As..
My issue is that while the HELP describe format options,SAVE AS give you only wav.