Pattern Based VSP Pump

If you are trying to hit a different target pressure at different times, I don't think you can do this using the Pattern (Relative Speed) approach. An alternate way of accomplishing it would be to set the pump to "Target Head" and the Target Head Type to "Pressure". Then you could set up a series of controls using Clock Time, changing the "Pump Pressure (Target)" to the desired value. If you only have a few changes (such as 12am, 6am, 12pm, 6pm), you can do this with Simple Controls and priorities.

For example:
If Clock Time >= 12am, Then Pump Pressure (Target) = VALUE, Priority 1
If Clock Time >= 6am, Then Pump Pressure (Target) = VALUE, Priority 2
If Clock Time >= 12pm, Then Pump Pressure (Target) = VALUE, Priority 3
If Clock Time >= 6pm, Then Pump Pressure (Target) = VALUE, Priority 4

However, if you have more than 5 changes, you will need to use complex conditions:
If Clock Time >= 12am AND Clock Time < 1am, Then Pump Pressure (Target) = VALUE
If Clock Time >= 1am AND Clock Time < 2am, Then Pump Pressure (Target) = VALUE
etc.

Just to add to Stephen's response - I noticed you mentioned that you're using V8i SELECTseries 5. The "target head" control action was added in SELECTseries 6, so you'd need to upgrade. To learn more about other things we've added in later versions, check out the "What's new in..." articles at the bottom of this page:

WaterGEMS and WaterCAD TechNotes and FAQs

More on using controls to change target head:

Using controls to change the target pressure / HGL setting of a variable speed pump

There was also this recent forum discussion:

Modelling of Variable Frequency Drive