Gallio 3.4 - no tests found

[tim....@comparethemarket.com]

I've just downloaded Gallio 3.4, I'm trying to run a set of unit tests from a command prompt.
The unit tests are built with NUnit.Framework, they run fine in Visual Studio 2010 using Resharper.
The following command : gallio.echo XsltUnitTests.dll
produces the following output :
0 run, 0 passed, 0 failed, 0 inconclusive, 0 skipped.

What am I doing wrong ?

Regards,
Tim.

[tim....@comparethemarket.com]

Here is the full message I'm getting when I run it :

C:\Dev\Trunk\XmlTransformation.Tests\XmlTransformation.Tests\XsltUnitTests\bin\D
ebug>gallio.echo XsltUnitTests.dll /v:Verbose

Gallio Echo - Version 3.4 build 11
Get the latest version at http://www.gallio.org/

Start time: 13:41
Initializing the runtime and loading plugins.
Verifying test files.
Initializing the test runner.
Running the tests.
Host started at 11/06/2013 13:41:52.
Running under CLR v4.0.30319 runtime.
Host stopped at 11/06/2013 13:41:54.
Host process exited with code: 0
Disposing the test runner.
Stop time: 13:41 (Total execution time: 2.883 seconds)

0 run, 0 passed, 0 failed, 0 inconclusive, 0 skipped