Goldie --
There is no way to do this in Project Server in any version (2002, 2003, or
2007). When you assign a resource to a task, the software applies only one
Cost Rate, and the default rate is found on Cost Rate Table A. To change
the Cost Rate on the task, you can apply the Task Usage view, double-click
the resource's assignment on the task, and then select the desired Cost Rate
Table. You cannot select multiple Cost Rates on a single task, however.
Where you have erred is making the resource's assignment a single task. You
need to break up this task into two separate tasks, based on the type of
work the resource will do, and then specify the correct Cost Rate Table on
each task. Hope this helps.