Calculating the correct score odds from the soccer match odds ?

Does anyone have any idea how you work out what the correct score odds in a soccer game should be with only the match odds and say the over/under 2.5 goal odds to work tthem out ? Does it have something to do with a piosson calculation? I know its possible as the bookies must do it to set odds in the first place. I'm looking for missalined prices to back / lay.

example :


Tranmere 2.5
Port Vale 6
The Draw 2.85

Under 2.5 Goals 2



Score Odds
0 - 0 11.5
0 - 1 13.5
0 - 2 29
0 - 3 85
1 - 0 7.4
1 - 1 7.4
1 - 2 17.5
1 - 3 50
2 - 0 11
2 - 1 9.6
2 - 2 16.5
2 - 3 50
3 - 0 20
3 - 1 17
3 - 2 30
3 - 3 85
Any Unquoted 10.5

From the above i could work out the home and away posibility of scoring from the match odds, my excel question is how do i work this into the goal odds using a piosson calculation?