Create Hybrid Rhythm Section Bars

Hi,
Please help me create a measure with the following items that are above the staff:
* Slashes for two beats
* Specific rhythm hits for the other two beats

Or, if this is easier:
How do I remove the stems from the first two beats of the measure to change a hit to a slash (i.e., I don't want to indicate quarter-note hits, but rhythm section markings)

I tried the following steps and hit a dead-end before step 3:
1. Right-click on the empty part of a measure.
2. From the context menu choose "Staff Properties"
3. Add a check mark next to "Slash Style"
4. Press "OK"

Please see image or file (with the bar further down on page one - sorry, there are no measure numbers but that's for a different forum topic).

Cheers,

O