The Viola have seen many changes in their squad this summer, but have brought in forward El Hamdaoui from Ajax and Argentine defender Roncaglia.
"I am very happy to be here and hope to be useful for the squad," said El Hamdaoui.
"My preferred position is second striker, as I like to play around the centre-forward. I haven't played a full match in a long time, but it won't take much to rediscover my form.
"I get on well with Stevan Jovetic and we will make a fine partnership."
Defender Roncaglia was also present at the Press conference, although fans staged a small protest at the lack of reinforcements.
"Serie A is one of the best Leagues in the world and this club is the place to mature. I am a centre-back, but can also adapt to a wider role.
"In Argentina the Coach also asked me to come forward for set plays. Walter Samuel and Nicolas Burdisso are my idols. Florence is a wonderful city and now the fans will be able to judge me for what I do on the field."