[R] Strange behaviour of as.Date function

[Vittorio]

Dear All,
I'm happily extracting data of temperature from an oracle db 
under R via RODBC. After manipulating the extracted data I put them 
into a data.frame 'dati' which is as follows:

> dati
         DATA tm.
UDINE/RIVOLTO tm.TORINO/CASELLE
1  2005-07-01            
22.35             23.80
2  2005-07-02            22.70             
22.85
3  2005-07-03            23.80             24.30
4  2005-07-
04            23.80             25.40
..........

and

> str(dati)
`data.frame':	11 obs. of  3 variables:
 $ DATA             :'POSIXct', 
format: chr  "2005-07-01" "2005-07-02" "2005-07-03" "2005-07-04" ...
 $ 
tm.UDINE/RIVOLTO : num  22.4 22.7 23.8 23.8 21.8 ...
 $ tm.
TORINO/CASELLE: num  23.8 22.9 24.3 25.4 21.8 ...
 - attr(*, 
"reshapeWide")=List of 5
  ..$ v.names: NULL
  ..$ timevar: chr "NOME"
  ..$ idvar  : chr "DATA"
  ..$ times  : Factor w/ 2 levels 
"TORINO/CASELLE",..: 2 1
  ..$ varying: chr [1, 1:2] "tm.UDINE/RIVOLTO" 
"tm.TORINO/CASELLE"
> 

You see that the first field DATA is POSIXct

Now
> dati[1,1]
[1] "2005-07-01 ora solare Europa occidentale"

BUT

> 
as.Date(dati[1,1],"%d%m%Y")
[1] "2005-06-30"

How come?
What is wrong 
with it (or better with me)?

Ciao
Vittorio