Saving XML plugins

Let me just start out by saying that I’m probably way in over my head with all of this, but I’m trying. I have made my lame attempt at an xml plugin for DA. I have saved it in the directory stated in the help section, but upon restart of DA, it’s not in the plugin section. I am currently using the trial version (maybe that’s why?) But I think that it’s more of something that I did or didn’t do. I wrote the first one in TextEdit and saved it as a Word XML. I then copied it over to OmniOutliner and saved it in that format as well. Neither worked.
Can someone help?

XML plugins use the standard .plist format of Mac OS X and only such files are loaded. You can use the property list editor of the developer tools to create such files. But TextEdit or any other plain text editor are also suitable as long as you use UTF-8 encoding.

There’s also a tutorial in the manual/help describing how to create XML plugins.