How to run sed in a groff *.mom file?

[Jörg Klein]

I want delete the first line of a csv file. I tried to use sed in the
name.mom file.
sed -e -i '1d' alpha.csv is not working.


.TS H
center, allbox, tab(,);
c c c c c c c c
c c c c c c c c
n n n n n n n n .

alpha,beta,gamma,delta,epsilon,Zeta,Eta,Theta

_
.TH
sed -e -i '1d' alpha.csv
.so alpha.csv
.TE