How to stop backing at 1000

[mixer456]

I am new to using gruss so i'm sure somone can help me with this.
When i attempt to back all runners in any race at say 100(keep in play) for less than the betfair min stake it allows me to do so. however if there is already a horse at 1000 it backs that at 2 pound stake not at the stake i pick. how do i stop this occurring?
in simple terms i back all horses at 100 for 1 pound before the off with keep in play tab clicked. if one of these horses is priced at the max 1000 it backs that using the 2 pound min irregardless of the stake i set.
Thanks for your help in advance.

[Captain Sensible]

Are you using the newer version of Betting Assistant, betfair changed the rules on the API to allow bets below £2 as long as they're £10 liability, I'm sure the newer versions are coded to take that into account.

[Captain Sensible]

meant £10 payout not liability*