formatting a multi-level catagory axis label???

Any suggestions on how to fix the attached chart would be much appreciated.

The chart labeled "Date & Time" is using a two level axis. But I can't get it to look right.

I cannot change how much is displayed. I've changed the interval between labels etc to no avail. Please help if you can. I'd like it to be legible even if the labels are spread out unevenl. Or even better would be to know how to set the labels at a certain spot say 12am for each day.

The other chart just shows the hours but that doesn't give the user an idea of what date it is. Thanks for any help!!!