From a quick search, here is a list of members of the Schweizerischen Tierarztlichen Vereinigung für Akupunktur und Homöopathie (STVAH):
http://www.stvah.ch/
(click on 'Liste der Inhaber des Fähigkeitsausweises)
Another idea: This homeopathic vet is highly recommended by a colleague - although he is in Zürich, you could contact his practice for a referal to someone in Geneva or Lausanne.
Kleintierpraxis FreiBär
Dr. Marc Bär
Freiestrasse 148a
8032 Zurich
044-422-4073
Also, homeopathy is fairly well accepted here - and a growing number of vets include some level of homeopathic treatment in their general practice. You can always ask a traditional vet if he/she can provide a homeopathic approach.