I dont think this works quite as you expect. I have never seen other than just plain anilla text boxes in people search options...
Do you have a reference that claims this is how it works?
I agree it would make sense, but unfortunately taxonomies are not integrated into every part of the platform (yet)
I researched adding taxonomy fields to the search options dialogue, and found this article, that describes pretty much what you try to do. He fails however, and even though he had PSS (MS support) on the case did not come up with a working solution.
Two other people found similar issues and chose different workarounds. Check here and here.
So, probably not what you want to hear.
One thing i noticed was that there is already are a taxonomy field in the search options OOB (that is if you enabled enterprise keywords or mapped Skills to a taxonomy as I have):
<Property Name="PersonKeywords" ManagedName="PersonKeywords" ProfileURI="urn:schemas-microsoft-com:sharepoint:portal:profile:SPS-PersonKeywords">
<EffectiveProperty Name="Responsibility" ManagedName="Responsibility" ProfileURI="urn:schemas-microsoft-com:sharepoint:portal:profile:SPS-Responsibility"/>
<EffectiveProperty Name="Skills" ManagedName="Skills" ProfileURI="urn:schemas-microsoft-com:sharepoint:portal:profile:SPS-Skills"/>
<EffectiveProperty Name="Interests" ManagedName="Interests" ProfileURI="urn:schemas-microsoft-com:sharepoint:portal:profile:SPS-Interests"/>
And these definately are not showing any taxonomy tree view, they just do what the other fields in search options do: prefix the search word with
<managedprop>:<searchterm> so i guess this is what you get in this release.:
(Responsibility:"test" OR Skills:"test" OR Interests:"test")