Possible BUG in snmpd.conf VACM 'access' directive

Hey,
 
I use these directives in my snmpd.conf file:
 
access ReadCommG "" v1 noauth exact v1-r-view "" v1-r-view
access ReadCommG "" v2c noauth exact v1-r-view "" v1-r-view
access ReadCommG "" usm auth exact v3-r-view "" v3-r-view
 
 
It seems that only the last directive affects the vacmAccessTable (it
overrides the previous directives).
1) Is this a BUG?
2) How can I overcome this?
 
 
P.S:
How do I specify an empty Write-View?
I used "", but it actually sets the write view to "".
 
Thanks,
Erez.