R help - Jul 2005 - Problem with filter() ?

Dear list,

This is ok :
> filter(1:5, 1, "recursive")
Time Series:
Start = 1 
End = 5 
Frequency = 1 
[1]  1  3  6 10 15

But this? :
> filter(c(rep(NA,5),1:5), 1, "recursive")
Time Series:
Start = 1 
End = 10 
Frequency = 1 
 [1] NA  0 NA  0 NA  0  2  5  9 14
> 
> version
         _                      
platform x86_64-redhat-linux-gnu
arch     x86_64                 
os       linux-gnu              
system   x86_64, linux-gnu      
status                          
major    2                      
minor    0.1                    
year     2004                   
month    11                     
day      15                     
language R                      
> 
Regards,
Matthew