I would like to re-open this SEVEN YEAR OLD discussion because I have the same question today...
The IRS site provided by Katherine did not seem to be 100% on point. The crux of the question is this: What does 414(u)(8)(B) mean when it says:
QUOTE
Each period of qualified military service served by an individual is, upon reemployment under such chapter, deemed with respect to such plan to constitute service with the employer maintaining the plan for the purpose of determining the nonforfeitability of the individual’s accrued benefits under such plan and for the purpose of determining the accrual of benefits under such plan.
At least one reaosnable interpretation would be to follow jaemons advice. In fact, considering the subject matter (i.e., protecting the rights of military personnel) and considering the ambiguity, would not the only reasonalbe response be to do just that? i.e., impute some reasonable level of hours? You might even credit them 40 hours a week since they would have been working 40 a week in the military.
I can find dozens of references that say "military service shall be treated as continuous service" but I cannot find defined anywhere what that means...