help

[Goofy]

Hi

i have to do an assignment for my university module.
i have to do a data type model for web services.for example to buy online .
i have to use UML case diagrams (and activity diagrams) to define business
processes (selling, browsing, buying) and secondly using UML Class diagrams
to define data types and business operations. Does anyone have idea how to
do it? does anyone knows examples of it on the net?

thanks