Trouble getting subdomains indexed

I have pinged 'em, submitted 'em to social bookmarks, I have done the Google add URL and domain in Webmaster tools type thing, I have Yahoo Buzzed 'em, I have provided Google with sitemaps, I have uploaded and verified that .html-file from Google Webmaster Tools on 'em, I have built just a few backlinks from articles and blogs, nothing extreme at all, about 5 links. I have a about 500 words of unique content on 'em, I have the basic Wordpress SEO-plugins installed, activated and configured, I have inbound links. The main domain have been indexed for a LONG time, if that does matter. But these haven't been indexed yet (5 days at the moment).

Help, input, suggestions, etc. would be greatly appreciated.