I might be wrong on this but I think the PFD Corp. deposits the money into an account that is used to pay the dividend. The Corp is required by state statute to make the requisite deposit; Walker can't veto something that hasn't been appropriated thus the Corp. has to make the deposit. 
If Walker's veto applies to a so called formality of vetoing an appropriation then one would assume the entire amount was deposited. But on the other hand, if the Corp deposited 1/2, according to Walker's veto then there could be a problem. If the money never made it into the account then there isn't an appropriation to veto and the Corp. is in violation of state statute. 
Finally, there's a question as to whether or not Walker can veto something that doesn't require an appropriation, which isn't required per state statute.
The other question I have is that the legislature did no indicate an amount of the appropriation. Walker just picked a number from the top of his head.  
Just my .02....