To place all object centers to the same location in Blender
In object mode
First put the 3d cursor where you want the centers to be. you can do this with LMB or shift-s will pull up a snap menu its self explanatory.
f9 key will bring up the mesh editing tab
Select all meshes. the easy way is to select all by type. on the tool bar in the 3d window is the select menu. Select-select all by type-mesh.
In the mesh editing tab is a button Centre Curso this button will move the object centers to the cursor. The widget will appear at the object center when you select an object.
The A-wing already has all the centers at the same location;).
I am using the DEMO of Blitz also and the .x file type works fine for me.