Does chapter 13 stop your ARM from going up?

We got served last week by sherriff the letter starting the foreclosure process. We have an ARM which is due to go up Jan 2011. We met with a lawyer 2 days ago that said if we file chapter 13 and our house appraises less than we owe on the first mortgage, that we can strip the 2nd and keep the house. My husband said that the lawyer told him our rate would not adjust during the time of repayment in the chapter 13. Is this true? I had to leave the meeting early so I did not hear this. I was under the assumption that just because you file 13 does not mean that the bank will modify your loan and that the rate and payment will still go up. I would appreciate any advice from people who have gone through this.