i think to resolve the issue you need 2 go into you ps3,s
VIDEO OUTPUT SETTINGS
this will make the ps3 choose the correct resolution settings itself automatically ,so that you dont have to search for them manually .I hope this has been useful in sorting you,r issue,i may have not xplained it very well but try it iam confident it will work..
let me know if iwas talkin hollocks lol
all the best