Mago with VisualD can't show top-level variables in the watch window

[Lewis via Digitalmars-d-ide]

I have the following minimal test code:

import std.stdio;
int TEST_CONSTANT = 999;
int main(string[] argv)
{
     writeln(TEST_CONSTANT);
     readln();
     return 0;
}

I'm running this in VS2013 with VisualD 0.3.41 and setting a 
breakpoint on the readln() line. In the watch window, I get 
"D0013: Error: Symbol not found" when trying to inspect 
TEST_CONSTANT. In contrast, if I create a local variable inside 
of main, I can view that just fine.

I have native edit and continue enabled, and Mago is set as the 
debugger in both the project debug settings and the global 
VisualD settings. I have Debug Info set to "Symbolic (suitable 
for Mago)", and cv2pdb turned off.

For reference, I get exactly the same behaviour when using the VS 
debugger and cv2pdb enabled.

Is this unsupported in Mago, or am I missing something?

Thanks in advance!