question about how to set isolation level with ias6.5

[fox hk]

Hi ias experts
Please help on following questions
1) Does any one know how to set isolation level of ejb / an app with ias 6.5 ?
2) what are the differences between "free-pool-size" and "ready-pool-size"? l have idea about read-pool-size but have no idea about what is "free-pool-size" and what it is used for. They are 2 tags of ias6.5 for configuring ejb
regards
fox