FSSO - About CN/sAMAccount for firewall policy

Hi everybody, i have configured FSSO on fortigate, the problem is when i create firewall rule, i want to  set source as sAMAccount (ex: test). But by default on FTG, source must be set by CN (CN=firstname test lastname test,OU=VCC,DC=vcc,DC=com). So my question is are there any ways to set source as sAMAccount? if yes, how can i do it?