Slitherine

This mission is impossible for me.
You need te defeat the enemy in a certain time, witch I can do, and with less than 100 casualties, witch I cant.
I played it over and over and I just cant defeat them without the max amount of casualties.

I've got;
3 preatorians; levels; 13, 12 and 8 (one with the special standard giving him the cool cirkel in battle)
3 legions; levels; 19, 18 and 11
2 auxiliary cavalry, both level 17
1 nobels; level 19
2 archers; both level 3
1 elephants; level 10
1 histasi; level 17
1 triari; level 20

and thats about it i guess, i had militia and skirmishers, but i disbanded them to get money to upgrade the rest. But that didnt help mutch...

Has anyone an idea to win this scenario?

ok, I did it!

No fancy stuf, just head-on attack!
That did the job!

head on is really nice for a reliable result, so long as they don't have a vastly superior battle line.