Qt Creator variables not expanded in Run settings for Bare Metal device

I'm trying to set up Qt Creator for debugging on a "bare metal" device. (ARM system, using JTAG POD with built-in GDB server.)

I think I can generally get this to work, but I'm experiencing an issue with the Run configuration: It seems like Qt Creator variables can't be used in "Executable" and "Working directory" settings. I get the normal "variables" icon and can select from a list etc., but it looks like nothing is ever expanded; if for instance I set Executable to "%{sourceDir}/executablename" and try to start debugging, I get

Cannot debug: Could not find executable for "%{sourceDir}/exectablename".

in the Application Output view.

I see this only for settings connected to a Kit for my device. With the same configuration under Desktop, the debugger generally starts as expected. Or if the file is actually missing, "%{sourceDir}" is replaced by the real source directory path in error messages.