I don't have the wildfire but I do have the One V so I can give you a good idea. I don't know of any tuts for doing this for the wildfire.
You do need to relock the bootloader... Boot into fastboot, plug phone into pc and and run the following on your computer with android sdk... fastboot oem lock
Phone may or may not reboot.
With phone in fastboot mode and still connected to pc run the ruu program on your pc and it will restock you
You can find all the Wildfire RUU's here.. http://www.htcruu.com/?dir=Marvel_MarvelC
I really can't tell you which but there appears to be 2 RUU's for the VM Wildfire
One is named
and the other is
RUU_Marvel_C_Sprint_WWE_VM_1.02.652.00_Radio_0.94. 00.0824_NV_VM_1.25_0815_PRL61007_release_219164_si gned.exe
Maybe someone can tell you which one you need. Technically the ruu should run a check to make sure it's the right phone but I can't say for sure.
Sorry I couldn't be a bit more helpful but hopefully this gets you going