The best person to answer this question is your VA Approved Local Mortgage Banker. Depending on the severity and/or amount of the charge off, you might not need to pay it before receiving a final approval on your loan. Underwriters have the discretion on matters of this nature, so often you'll get a loan approval requiring the charge off is paid prior to closing. But there are instances when the Underwriter might not require the account to be paid.
Find a VA Approved Mortgage Banker in your area. Identify the Loan Originator in that company with at least 15 years experience, including experience working with Veterans. You can look up a Licensed Loan Originator's License and work experience on the National Mortgage Licensing System's website (NMLS).
VA website: http://www.benefits.va.gov/HOMELOANS/purchasecashout.asp?exp
NMLS website: http://www.nmlsconsumeraccess.org/
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