  We present the first detailed joint modelling of both the timing and spectral
properties during the outburst decay of transient anomalous X-ray pulsars. We
consider the two sources XTE J1810-197 and CXOU J164710.2-455216, and describe
the source decline in the framework of a twisted magnetosphere model, using
Monte Carlo simulations of magnetospheric scattering and mimicking localized
heat deposition at the NS surface following the activity. Our results support a
picture in which a limited portion of the star surface close to one of the
magnetic poles is heated at the outburst onset. The subsequent evolution is
driven both by the cooling/varying size of the heated cap and by a progressive
untwisting of the magnetosphere.
