Yes or /MANIFESTFILE:filename
Dangerous option: if you specify an existing file, it gets overwritten!
The right option seems to be /manifest
input:MyFile.xml, but apparently it requires linker version 14, difficult to set up etc, and eventually it will ask you for a non-existent mt.exe :(
EDIT: Finally, I managed to convince LINK 14.0 to perform its task. It's messy, as usual

- the relevant commandline options are
/verbose /manifest:embed /manifestinput:MyFile.xml- you need at least \Masm32\bin\mspdbcore.dll
- the linker will choke unless you move MT.EXE into the bin folder
- if you are lucky, MT.EXE sits in C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin\mt.exe
- if you don't like the /verbose option, try without; on my machine,
the infamous -ologo error pops up
Anyway, even for X64, polink and a standard XP manifest with processorArchitecture=
"*" works fine :P