Weirdness when writing to pseudofs file

Hi

I'm fiddling with lindebugfs, which is based on pseudofs. When writing
to a file,

this works: # echo  1 >> /path/to/file

but this does not: # echo 1 > /path/to/file

"Operation not supported." is returned before the pseudofs code is even
entered.

Is this expected behavior? (if so, why?)

Thanks in advance
/Johannes