Dave,  I sincerely hope you already solved your problem, since it is May now and you wrote your note in February.  But, the system registers no reply.  And, I just managed to place variant time signatures in my composition. 

To alter the time signature, click the time signature button, just below the Options tab.  Then, right click the first measure you want changed.  A drop down menu appears.  Choose your time signature.  Go to the measure for which you want to change again / change back and right click, doing the same procedure.

Here's to beautiful music!  Jana