Evaluating Tokens with PHP

Dear DS experts,

I've got a small problem: I have a content type 'arrangement' with a field, that can contain several values, e.g. 'excursion' and 'lecture'. I am displaying teaser, full node and so on with Display Suite on Drupal 7.8, and THANK YOU for DS, it's GREAT, and I want it to display like this:

'Excursion and lecture: Lüneburger Heide'

I have added a code field for the header using tokens:

[node:field_aktivitetstype]: [node:title]

It displays:

'Udflugt, Foredrag: Lüneburger Heide'. Flaw: both values have a capital first letter.

I tried a dynamic field, but that doesn't seem to be the way to go. Then I tried to just ucfirst(strtolower()) it - I can use PHP code, right? (I'm a Drupal noob), in many combinations, and nothing worked right. I have access to the entity object, but don't know how to do get the field value(s) from it.

Please help me, and I promise to get stronger and fight for other Drupal beginners!