Month doesn't appear in the axis for last 12 months

Question

Hi !
I have created a graph which gives records for the last twelve months, my formula is:
if {Commande.DATE} >= dateadd('m',-12,currentdate) and {Commande.DATE} <=currentdate then {Commande.DATE}
At this point everything's fine ,
I have to create another formula to have Month name
from today which mean ,the order should be like this on my graph axis, 1st last month is febuary and last 12 months from today is March
March - April - May - June - July - August - September - October - November -December - January Febuary
here is that formula which I have called Month Sort order:
If month({@last12months})=01then
"Janv" else
if month({@last12months})=02 then
"Fév" else
If month({@last12months})=03then
"Mars" else
if month({@last12months})=04 then
"Avril" else
If month({@last12months})=05then
"Mai" else
if month({@last12months})=06 then
"Juin" else
If month({@last12months})=07then
"Juil" else
if month({@last12months})=08 then
"Août" else
If month({@last12months})=09then
"Sept" else
if month({@last12months})=10 then
"Oct" else
If month({@last12months})=11then
"Nov" else
if month({@last12months})=12 then
"Déc" else ""
in the Graph/Chart expert ,in the resulting dialog box I have set  the following options:
On Change of: i have set the formula Month Sort order which will bring me the  month name  and for the order I have set in the Original order .
It works fine I retrieve records for last 12 months but on  my axis ,the name for
the last 12 months doesn't appear  in this case ( March) it is blank ,I have the records for March but not the month name March in my axis  it show april  to febuary  but not March
Thank you for helping me

Answer 1

Thank you for your reply , but this doesn't solved my problem  ,
I'm using a data from SQL2005 which is a stored procedure ,they have created a datefield named "DATE" and group the data the 1st of each month in this SQL stored procedure ,the only day for each month that I have in this data is the first of each month for each record found ,so I've changed the formula for this, to get records the 1st of each month for the last 12 months :
the new Formula for is:
if >= DateAdd("m",-12,CurrentDate) - day(CurrentDate)+1 and
<=DateAdd("m",-1,CurrentDate) - day(CurrentDate)+1 then
this condition formula bring me _Null datefield_ ,and this is why I see a null label axis at the bottom,do you have an idea how I can eliminate the null datefield , I need to have only the last 12 months data on this graph but I need all data for the past 3 years for 2 other grah on this same report
Thank you very much ,