Most papers use the Hosking (1980) to detect whether the multivariate GARCH model used captures all heteroskedasticity effects. However, Bauwens (2006)(p.101-102) do state shortcomings of it, when applied in this context, but they do also mention that it does provide a useful diagnostic in many situations.
So, I would like to ask you, whether a better test exists (and if it was available in R or Matlab would also be nice).