vApp not able to have property with empty value int

Hi, I am creating a vapp, and all of my properties seem to work fine except the type of int with an empty value.  Every time I try to deploy the ovf template, it tells me "invalid value" unless I set a default value in the ovf.

I have tried:

ovf:value=""

ovf:defaultValue=""

But the only thing that ever works is when I add:

ovf:value="<integer>"

According to the docs, it should work fine, but it is not.  Anyone run across this and have any ideas?

Thanks,.

Greg