A user noticed me on the fact that Finch RC1 was not working correctly with his website, which is running Mambo CMS. As Mambo is very popular in the PHP community and it does apparently work with w.bloggar, I wanted to fix this. This has turned out harder than I had guessed, but I think it's OK now.
The first problem was that Mambo supports multiple blogs per user. Finch does not do this yet, but I have received request to add this feature, so in the future, this will be solved. For now, you must enter the ID of the blog you want to work on in the Settings dialog. This ID can be a name or a number, depending on your blogging engine. In Mambo, it is a number, so you have to figure out what the numerical ID of your blog is. You can often find this out by inspecting the URL of web pages displaying the blog.
A second issue turned out to be a real bug. The MetaBlogAPI implementation I created follows the one implemented by .Text (the blogging engine I use myself). This turns out to have a small difference from the spec: a list of categories is returned as an array, while the spec states that it should be a struct of struct. Many other implementors seem to have the same error, so the error is also a de facto standard. Mambo CMS follows the original spec. Finch now supports both.
Third thing: a bug in the MetaBlogAPI implementation in Mambo: creation dates are returned as strings in stead of dates. Finch now converts this string to a date itself. I really feel that Mambo CMS should fix this, but then again: their installed base is huge, so I'll just try to manage (so does w.bloggar apparently).
Download RC2 here