When refreshing a datasource stored proc I lose all SP parameters

[eo]

SQL Server 2005.

I have comprehensive stored procs serving the SSRS reports. When making a change to the SP it seems normal to click on the refesh button in SSRS > Data tab > Datas source
But every time I do this, I lose all the objects on the report (including the parameters) from the SP.

I them have to close down the project without saving to get all back to normal.

I have no idea how else to feed SP changes into the SSRS report

Any ideas?

EO
Hertfordshire, England