Jiu-Kang Yu has an article "Bruhat-Tits Theory and Buildings" which has appeared in  "Ottawa Lectures on Admissible Representations of Reductive $p$-adic Groups". It doesn't directly address your question, instead it contains a guide to the literature on Bruhat-Tits buildings.

From memory there are two versions of this article. There is a <a href="http://citeseerx.ist.psu.edu/viewdoc/download?rep=rep1&type=pdf&doi=10.1.1.217.9089">26 page pdf</a> version. It is a long time since I saw the published version, but if I remember correctly it is quite different from the pdf and very hard to find.