What Stefano suggests will work. I even use a Dual() load inline instead, but it's fine. But what about one code line based on a variable you already have in your script and, if you dont, you can easily create it? Check the top part of your Main tab in your script. The frist few lines are environment variables used to set the money, date and timestamp formats, separators and so.
Ok, create a new one with the name of the months as you wish
SET LongMonthNames = 'January;February;March;April;May;June;July;August;September;October;November;December';
Now, in your calendar table use the SubField() function to get the correspoding value to your numeric month value
SubField('$(LongMonthNames)', ';', Month(DateField)) AS MonthName,
And you are done! This way you don't need to use an inline table to link to your calendar table. You can even use the MonthNames variable that already exists in your script and no need to create a new one. And you can even change the language for the months or use two variables with month names, (for example, Spanish and English).