how to spin-up in carbon-only of clm4.5

[ncepulee@126_com]

hi,all! i want to run carbon-only mode in clm4.5. As far as i know,i can use suplnitro = 'ALL' to realize it。 However,i wonder how to spin-up under the carbon-only mode. when using C-N mode,spin-up include two steps-accelerated decomposition and normal decomposition。while suplnitro cannot be set to ALL under accelerated decomposition spin-up in carbon-only mode, how can i achieve the equilibrium state like C-N mode? thanks a lot for anyone's advice.