vacuole transport in pombe

[T.J. Young]

Hi,
I'm expressing a protein in pombe as part of my PhD and I think it's going 
to the vacuole and being rapidly broken down.  I was wondering, can you 
inhibit vacuole transport in pombe?  I've read you can do it in cerevisiae 
with 0.4M NH4Cl but I'm not sure what growth stage you should add it.  
Failing that, are there any prombe transport mutants about?  I can't find 
any in the literature.  Thanks in advance,
Tim ;-)