The rosetta example dax generator has:

// executables and transformations
// including this in the dax is a new feature in
// 3.0. Earlier you had a standalone transformation catalog
Executable exe = new Executable("rosetta.exe");

// the executable is not installed on the remote sites, so
// pick it up from the local file system
exe.setInstalled(false);
exe.addPhysicalFile("file://" + cwd + "/rosetta.exe", "local");

// cluster the jobs together to lessen the grid overhead
exe.addProfile("pegasus", "clusters.size", "3");

Which comes out as:

<executable name="rosetta.exe" installed="false">
<profile namespace="pegasus" key="clusters.size">3</profile>
<pfn url="file:///home/rynge/src/pegasus/pegasus/examples/grid-rosetta/rosetta.exe" site="local"/>
</executable>

When I plan it, I get:

2010.11.18 06:40:34.255 PST: [WARNING] Unsupported nesting for element profile in parent element executable