how to set constrains in MPF2_DoMPFit

Hi IgorPro Experts,

I have recently started using Igor Pro for the analysis of my experimental data. I like a great number of possibilities given by this software, however, I am still a beginner, and need your valuable advice.
I perform a fit to a large array of spectra (~10000) using MPF2_DoMPFit procedure. The example of the fitting subroutine from Igor Pro manual help to reach error free fit. However, I cannot apply constraints so that the fit is done to the physically reasonable signals. My question is how to apply restriction in the course of the use of MPF2_DoMPFit (Is there a string wave, in which I can apply 'hold' option with respect to the position of the signal? Are there tricks to predefine parameters for FuncFit, which is called by MPF2_DoMPFit?).

Thanks a lot!