Hi Claudio, thanks for your query.
There is no right or wrong answer here.
I think the best option for ease of reading would be to put both your CV and the cover letter as attachments to the e-mail. Then in the text of the e mail, simply write:
To whom it may concern,
I wish to apply for the position of . Please find attached my CV and covering letter for your consideration.
I look forward to hearing from you
I hope that this has helped. My company, Words Worth Reading can review your CV if you so wish. Please visit us at www.wordworthreading.co.uk if you wish for us to assist you.