SiteKreator doesn't have any of the HTML editing features you mention. I think this is done to keep the code controlled so that you can easily do things like change the template across the site without any problems.
Anyway - the SiteKreator team kindly looked into the issue and told me that the Trumba code does work with the Seasons, Minimalist and Standard templates. They offered to tweak the other templates for a reasonable engineering charge but I actually quite like the minimalist template and the site is progressing nicely.
SiteKreator ( http://www.sitekreator.com )really is a nice tool for anyone that wants a quick and easy yet professional looking site. I'm glad that it now works with Trumba whichis great for anyone that wants a quick and easy yet professional and powerful calendar 😉