Email Server II Web Interface

Sorry, this may be a bit parochial for the web designers, but I would like for the Web Interface of SuSE's Email Server II to be in English primarily and Spanish alternatively. In this package, the administrator has the option of selecting the default language per user, however, the only languages to select are EN and DE. I don't know how to change this. Out of the box, it is in English with German, I can change the Web Interface back and forth from English to German, by clicking on the German and British flags, but I don't know how to add any additional language support or change it to Spanish and English. Please help me. What must I do to be able to select Spanish? Thanks Randy