JJeffrey -- Actually, Hilton has the same option of submitting your missing credits electronically through
http://www.hiltonhhonors.com . Log into your account, click on "Member Services", then select "Missing Stay Request".
And
chix is right, you can usually just call in your missing stays. In fact, both Hilton and Starwood allow this up to a certain limit of stays/points.
[This message has been edited by Eugene (edited 12-04-2001).]