The solution to this problem can be found in the following paper:
C. Almeida and A. Saa, Am. J. Phys. 74, 154 (2006)
"The Radiation of a uniformly accelerated charge is beyond the horizon: A Simple derivation"
Free access: http://arxiv.org/PS_cache/physics/pdf/0506/0506049v5.pdf
In...