svydesign and prop tables: how to compute CVs and SE?

I am in the need of estimate the CVs and SE from a proportion.
I mean, I have a variable with categories. I need to obtain the errors from the proportions of each category over the total sum.
I can total estimates flawlessly the CVs or SE with svytotal, but I'm missing something with the ratio.
Can you guide me, please?
Thanks for your time and interest.