Using udf 0.9.2.1 I was only able to copy 32 megs worth of data to a udf filesystem.
1.formatted hard drive partion with udf.
mkudf --blocks=1263472 --blocksize=2048 /dev/hdd1
2. mounted hdd1
mount /dev/hdd1 /mnt/udftest -t udf
3. copied files from /usr/src/linux to /mnt/udftest.
At around 32 megs the filesystem reported that the device was out of free space. When df was ran filesystem still had around 98% free on it.