Daily vs Hourly resource rates

[Dave Barker]

EPM 2003

We need to change resource rates in the Enterprise Global Resource Pool from hours to days. We are not changing the actual value of each resource, only the units it is expressed in (i.e. hours to days), hence would not expect to see any changes in cost.
When we do this, MS Project displays different costs (both actual and remaining) than before. What EPM seems to do is take the new day rate, divide by 8 hours and multiply by 7.4 hours.
The default EPM standard calandar states 7.4 hrs per day from 9 til 5 with a small break at lunch. We also have a second calandar which is set to use the same hours in a day, but includes bank holidays.

can anyone help and say how we can make EPM show day rates and not change the value
of the task assignments