How to run multiple commands with an extra target in QMake

I am making extra targets using qmake, and I'm trying to do two things at the same time: make a new folder, and copy a dll into that folder. Both action separate work fine, but the two together don't work.

something.target = this

# This works:
# something.commands =   mkdir newFolder
# This works too (if newFolder exists)
# something.commands =   copy /Y someFolder\\file.dll newFolder

# This doesn't work:
something.commands = mkdir newFolder; \
                     copy /Y someFolder\\file.dll newFolder

QMAKE_EXTRA_TARGETS += something
PRE_TARGETDEPS += this

I thought this was the right syntax (I found similar examples for example here and here), but I am getting the following error:

> mkdir newFolder; copy /Y someFolder\\file.dll newFolder
> The syntax of the command is incorrect.

Is the syntax different on different platforms or something? I'm working on Windows 7, with Qt 5.0.1.