Views: users show as ID instead of username

I'm using Votingapi with Fivestar and have some trouble with Views Integration. If I understand it correctly, the integration is provided by Votingapi, so hopefuly I post this on the right place.

Here is a picture of the view

As you can see, the user who cast the vote is displayed as an ID. Is there a way how to display it as an username? I looked around but found now way how to do that, so I came to a conclusion it is probably a problem in the code.

If you need more information, this is how I created the view:
1) Created a new View to display nodes
2) Created a relationship with "Node: Votes - Votes cast by users on nodes"
3) Created a new field set to display "Votes: User - The user who cast the vote."

(then added a few other field and filters, which are irrelevant).

Thanks,

Jiri