HI Martijn,
I already sent you a reply in a separate communication, but for the benefit of the community, I'll repeat it here.
If you can live without the matrix format, here's what you could do: First, define 4 custom fields for use cases: Responsible, Accountable, Consulted, and Informed. Then, fill them in, referencing actors by name or by ID, separating multiple actors by space or comma (doesn't matter). You can then create a custom Word or Excel report that shows the relationship in both directions: for each use case show the referenced actors, and for each actor show the use cases that reference it. Take a look at the Requirements Cross Reference report - this report would be similar in nature.
You'd probably want to separate references by kind (i.e. put all the "Responsibles" together, etc.). Here's a rough outline of how you could do that:
$repeatUseCases
$ID $Name
$groupReferencedActorsByRefLocation where InCustomField = True
$RefLocation:
$listCurrentGroup $ID $Name
$endgroupReferencedRequirements
$endrepeatUseCases
Output would look like this:
UC-123 Make Lunch
Responsible:
Cook
Chef
Accountable:
Restaurant Manager
...etc...
You'd also want to add a separate section for Referencing use cases for each actor, which would be quite similar to the above.
This would create a report that has the same information as a RACI matrix, just in a different format.