how to change the word 'preface' in Scientific Workplace 5.5

how to change the word 'preface' in Scientific Workplace 5.5

I'm having a problem with the language in SWP 5.5. I am writting a text in
spanish, so I am using the \usepackage[spanish]{babel} sentence at the
beginning of the document and it works perfectly with all the format.
However, the word 'Preface' still appears in english after the ToC in the
pdf output. Any help is welcome.