Hello,
that's what I thought, too. Then I've created a simple parser to resolve this issue. The creator of the plugin refuses the pull request. He pointed out that it seems to be a limitation of plantuml.jar - he cannot get a full parsed title from outside with resolved builtin functions. Because of this my change for the plugin is somehow redundant to code of plantuml.jar - and so far not necessary. I'm not familiar with java and the plantuml api. I cannot check and nor implement this api if necessary. That's why I'm asking here.
Regards