assigning pie chart colors for pegas haploNet plot

I am trying to plot a series of haplotype networks using the plot function for haploNet in pegas and am trying to include population frequencies using the pie chart attribute.

I have been able to assign population frequencies successfully (the post on stackoverflow was very helpful http://stackoverflow.com/questions/25755930/how-to-plot-pie-charts-in-haplonet-haplotype-networks-pegas).  

But, I am not able to control which colour gets assigned to each population. It seems that col=rainbow() is automatically being called but I would like to set specific colours to my population. How can I do this?

Many thanks,

Cynthia Riginos