In my many Romani campaigns I´ve gone with several different approaches, the first being just not giving a crap about Senate offices.
Second time around I tried mainly to use Consuls and Praetors, but when their terms of office expanded I´d just pretend that they´ve been made Pro-Consul or Pro-Praetor over that particular war.
Third time I did as Konny said and held my own elections every year, often even making up my own stories as to why this particular guy was chosen to be say Consul.