"bitcoin-qt -conf=..." stops working with v0.9.1 bitcoin-qt

[mhps]

I am using  Win7 32bit

For security reasons I don't install bitcoin-qt in standard directoy and use a none standard datadir.

My bitcoin-qt is installed as c:\abc\bitcoin\bitcoin-qt.exe . My datadir is f:\def\btc so the .conf file is f:\def\btc\bitcoinqt.conf
I define

Code:

datadir=f:\def\btc

in bitcoinqt.conf. And I always use 

Code:

c:\abc\bitcoin\bitcoin-qt -conf=f:\def\btc\bitcoinqt.conf

to run the wallet. I have been using the above with v0.8.1 bitcoin-qt , LTC and other coins without any problem.

After upgrading from v0.8.6 to v0.9.1 bitcoin-qt it either doesn't start (hangs there forever)

If I start v0.9.1 bitcoin-qt  without -conf= it starts fine.  It shows that at least the installation is correct.

This seems to be a bug. It breaks drop-in substitution with the v0.9.1 bitcoin-qt. I posted in the tech support forum but didn't get a  meaningful answer.