It looks like adding
default xml namespace "http://tempuri.org/MyTest/MyTest"
before your myXML declaration will allow you to access its non-namespaced (or default namespaced) children.
I can't say I understand the syntax, but it works.
Sometimes it works... but very often the ExtendScript ToolKit "hangs" when I try to run, and sometimes I just get "Execution finished" as result, and nothing was written out in the console window...
If I press F11 to enter debugging instead of running, the test script (with the default namespace line) becomes inaccessible almost every run, and I have to restart Indesign and / or ESTK. I have restarted my computer several times as well, the last couple of hours. I have also trashed the InDesign preferences, but the problem persists.
Also, the default namespace seems to stick to the InDesign session or something... since removing it and running the same script (in the ESTK by pressing F5) returns the same (correct) result, without the default namespace. And the debugger/InDesign freezes/hangs even with the default xml statement removed, as long as I have tried to run with it before.
Can these problems be repeated, are they known?
These tests I'm doing in CS4 (since the code need to work for CS4).
Whoops. Sorry about the missing "=". I can reproduce your problems running the script (on CS4 on the Mac) from the ESTK, but only if I'm running it in a persistent custom engine. I assume you are too, which would explain why the default xml namespace persists across invocations of your script. You may want to get that namespace declaration (and whatever you're doing that depends on it) out of the global namespace if setting it for a whole session is a problem.