Batch to rename files?

[RJMacReady]

I need to find 0KB files in a directory, then replace the file with a pre-designated template file (blank.tif) but retain the file name. For instance, c:\temp contains test.tif and test1.tif, both with 0KB file sizes. The batch file would go in, grab blank.tif from c:\temp\replace (already set up), copy it to c:\temp but renaming it to test.tif and test1.tif (the size would remain the same from c:\temp\replace.)
I have a partially effective batch right now that finds and renames 0KB files, but need some help to relicate the desired behaviour described above. Any ideas? Here is the batch right now:

@echo off
setlocal
set FileMask=*.*
set LogFile=C:\temp\FindZero.log
set Size=0
if exist "%LogFile%" del "%LogFile%"
set Count=0
echo Searching for files of %Size% bytes size ...
for /r %%a in ("%FileMask%") do if %%~za==%Size% (
echo %%a
>>"%LogFile%" echo %%a
set /a Count+=1
)
ren *.txt *.jpg

echo %Count% files found.