I'm foxed!

I'm wanting to create lovely themed primary & secondary menus to help with distinct look/feel and colours etc for each section of my site. This works great with the views module, creating lovely looking lists of pages within my taxonomy of content 'channels' - I can use the list's 'class="active"' parameters to make it look as lovely as I want to as I progress through the menu and display my views lists.

Trouble is, when I view a specific node, the class="active" parameters disappear off my menus, making them bare and boring, despite selecting the right taxonomy terms for the node and setting the node's url alias sensibly.

Here's my example...

site.com/news - my first 'views' list for all nodes with the term 'news' or its children;
site.com/news/world - second 'views' list for all nodes with the term 'world news'

beautiful so far - menus look loverrrly. but here's the trouble... i jump off any of my 'views' lists to a node, e.g.:

site.com/news/world/060919a - node with taxonomy term 'world news' (even set the Primary Term as e.g. 'news' using primary term module) and url alias set as 'news/world/060919a'.

The menu system page in the API seems to suggest that the menu system should work things out - but it isn't! Is that because the system URL (i.e. node/297 or whatever - rather than the url alias) isn't of the form 'news/world/xxx'...?

Anyone got any ideas how I can get my menus to keep their class="active" parameter when I jump off to a node with the appropriate taxonomy terms...?

How can menus be themed...?