Not sure what to do

My husband recieved a felony charge several years back for being at the wrong place at the wrong time. He was with people who robbed a house and stole guns along with several other items then had my husband pawn them. He was young scared and did as they said. Well he ended up being the one charged for the crime since the only link was to him. He took several lie detector test and passed them all and was cooperative through the whole process. He had never been in any kind of trouble at all with the law and they made him a plea deal that if he plead guilty it would be expunged as soon as his probation was done. Well all that has been done with for well over a year now, he has called the county he was held at and they said that since he plead guilty it can not be expunged. Is there any way we can get around it. He really loves hunting and wants to be able to teach our daughter and be able to live a life without this following him.