Either download and install the stock verizon rom. this will install verizon's ext rom.
But be warned. the latest verizon rom has a newer bootloader also. you can search the apache forum for the new rom without the new bootloader.
Or you can downlosd this
ftp://ppcgeeks:ezupload@up.ppcgeeks....nded%20ROM.rar
This will give you a blank ext rom even when you do a hard reset.
I suggest the blank ext rom since your cooking all the verizon info into your custom rom. so you dont need the ext rom,=.