Thanks for your replies. I'd like to keep using the Metro stencil as I've been able to get most of the work done in that so far...my aim is to print this rather than use it programatically like David's.
Vojo: I'm looking for a 45 degree angle a bit like those used in the bottom left corner of David's diagram for the airport...a 45* angle with a slight curve, rather than a 90* angle available in the Metro shapes. In terms of callouts, I'd like to use the Metro shapes (same characteristics of always-horizontal text and marker shape stays the same) but with a block (like David's) rather than a triangle.
Aledlund: It's great to see that diagram and that's what I'm aiming for, but don't need the application sat behind it. It does show it's possible in Visio. Thanks.
Thanks, both, for your responses.
Ben