& &\

![image](fig6.eps){width="100mm"}

![image](fig7.eps){width="178mm"}

In order to fit the optical-to-X-ray SED, we combine the averaged 300V optical with the X-ray spectra. We choose to include the 300V spectrum in the SED to investigate the significant dust reddening reported by @Fynbo09. Also, the larger spectral window coverage of the 300V as compared to the higher resolution spectra makes it more suitable to investigate the SED. The SED time is chosen at the logarithmic mean between the two 300V observations (3945 s). Using the *Swift* spectrum repository [@Evans07; @Evans09], we extract the X-ray spectrum from a narrow time interval (3690–4200 s, logarithmically centred on the SED time), and use its count rate to scale the X-ray spectrum extracted from a larger time window (3690–106130 s) and with a better signal-to-noise (S/N). This approach assumes no spectral evolution in the X-ray spectrum, as confirmed by extracting spectra for different time windows and by the constant hardness ratio. This allows the optical and the X-ray spectra to be compared in flux. The 300V averaged spectrum was cleaned (absorption lines removed and frequencies bluer than Ly$\alpha$ excluded) and corrected for Galactic extinction. The optical spectrum was then binned into 22 bands (192 Å) in order 