allowing program to keep pc awake

so here is my issue, i have a ftp server that goes to sleep after 2 minuets of inactivity, cool it will save me on my electricity bill, i send a magic packet to wake it when i need it, hears the issue, filezilla server will not keep it awake when somebody is logged into it, so when im out and about, i can wake it up, just into it with filezilla client but it then will sleep after two minuets because apparently it doesnt realize i am logged into it. how do i allow this program to keep the pc awake, i have a feeling that if there is a way then it will keep it awake forever considering the server end is allways running when the pc is on, id like to set it to stay on if somebody is logged in. but i may have to see filezilla forums for that .