In Siman 5 of R' Mordechai Baneth's Parshas Mordechai (published post-humously) you have part of a Teshuva delineating many questionable Responsa in Besamim Rosh (see here). Interestingly, there is another list by Rabbi Baneth in והמה בכתובים, העתקות כתבי־יד מנחלת האחים לבית יעללעש pg. 20 (there are many important letters relating to the controversy there). My apologies for the lack of clarity of the scan. If someone has the book and can send me clearer scan, I would update it:
I'm not cerain why he used the term "Minus" for most of this list!! Interesting that it is somewhat different then the list in Parshas Mordechai.
A letter from R' Benet to R Tzvi Hirsch Berlin, the fsther of R Saul can be found here. - literary supplement No. 6 53-55 No. 9 140-141.
On the publisher of this letter, Solomon Rosenthal - See YY Greenwald - Toldot Mishpachat Rosenthal (available at Hebrewbooks.org). [Update: I see now that this is the very same letter that appears in Parshas Mordechai - of course without credit to Orient.]
[In the same newspaper, I noticed a review of ShuT Chasam Sofer See Issue 15 pg. 247 of the PDF, and an article by Raphael Kirscheim on "Juden und Pesach" pg. 185 (202) of PDF.]