[morticaixavier]

I know this is going to sound crazy but it has worked consistently to stimulate Brett several times for me. Try adding some pelletized hops. I often brew (sometime award winning) saisons finished with Brett and a little dry hopping does this style a favor. The first time I realized the effect, I had a secondary pitched to Brett for about 2 weeks with no apparent activity. A couple of days after adding the dry hops, fermentation activity was apparent. I've repeated this process at least 5 time with the same results. After adding the hops, final gravity is reached in about 4 weeks. I've done this with Brett pitching gravities from 1.008 to 1.015 to finish from 1.002 to 1.004. For my taste, I use Brett fermentations at 60F, so your temp is fine (more funk, less fruit at higher temps). I normally use 0.5 to 1 ounce of Saaz.

My theory is the pelletized hops have trapped air in the pellets and this stimulates the Brett.

if this is true then whole hops should work even better as they will have a lot more air. although they won't sink into the beer in the same way.

[brewinhard]

Most likely due to adding nucleation sites to your beer (the surface area of your pellets) that allow the CO2 to give rise in your beer.  The rising CO2 might help to kick the brett up in suspension so they can ferment any residual sugars/starches.  I have heard that brett sometimes works better/faster under a bit of pressure as well.