I just retested this. Surround with can be configured to create a block comment. You may just have just gotten confused by the meaning of the "Surround with" checkbox on the aliases dialog, or you did not realize that surround with was configured through aliases in the first place. Unfortunately, it is't blatantly obvious.
To create a block comment surround with alias.
1) Go to Tools > Options > File Extension Setup...
2) Select the file extension to customize, for example, "c" for C/C++
3) Switch to the General tab, and click on "Aliases..."
4) Check the "Surround with" check box to customize surround aliases
5) Click "New...", type in the name for the comment alias
6) Fill in the following for the comment text.
/*7) Click OK when done
Of course, a more direct way to configure block comments is to go to "Document" > "Comment Setup...", and configure your block and line comment preferences. Then you can use "Document" > "Comment Block" or "Comment Line" to comment out a block you have selected.
Let us know what works best for you.