[R] merge.zoo and fill

[Research]

Hello again,

I merge different zoo time series with prices at different dates. This 
returns a multivariate zoo object with NA's at various points i.e.,

2010-02-28     NA     NA      NA       NA   850.2  2444.4     NA      
NA      NA      NA     NA      NA       NA
2010-03-01   61.1   55.3    61.5    81.24      NA      NA 1712.2     3.3 
11139.3   163.7 2242.4  9015.6  109.791
2010-03-31     NA     NA      NA       NA   846.5  2439.0     NA      
NA      NA      NA     NA      NA       NA
2010-04-01   66.9   49.4    65.7    84.48      NA      NA 1700.6     3.8 
11203.0   164.4 2245.7  9064.5  109.887
2010-04-30     NA     NA      NA       NA   838.0  2440.0     NA      
NA      NA      NA     NA      NA       NA
2010-05-01   66.6   45.6    65.7    73.84      NA      NA 1705.3     4.0 
11252.0   165.1 2248.4  9113.9  110.065

Will the "fill" parameter of the zoo.merge() allow a missing value for 
each zoo object merged  to take the last available (previous in time) 
price for that particular time series or one has to do that using  the 
na.locf() command afterwards?

I want ot keep the series as zoo and not convert to other formats or 
interpolate (as in the FAQ)....

Thanks,
Costas