You are using Finale 2009, right?
In Finale 2009 you can do it like this:
1) Selection Tool.
Select the region you want repeated - including the partial measure at the beginning and the partial measure at end of the region.
2) Plug-In menu > Measures > Mid Measure Repeats...
If your pickup measure was created with the feature "Pickup Measure" (in the Document menu), playback isn't correct:
The feature "Pickup Measure" uses a full measure with inserted invisible "placeholder rests" at the beginning of the measure.
To get a pickup measure with correct playback, instead create the pickup measure by using the Time Signature Tool on the first measure.
In the dialog box "Time Signature", click the button "More Choices" to expand the dialog box, and get a pane where you can specify, that the time signature in the first measure should display as 2/2.
Finale 2011c, 2012c and 2014c, Mac OS X 10.9.3, Dolet 6.4 for Finale, Finale user since 1996