Derived Column transform to check ISNULL on multiple columns?

Hi -

This is for Sql 2008R2.

I am working on a ssis package to move some data from a staging server to another sql server for a reporting db.

One of the requirements is that i convert three name columns (First, Middle, Last) to populate a FullName column, with the format as LAST, FIRST MIDDLE.  Not all of the rows have a value in all three columns, so i need to check for NULL and replace with a blank string.

I am trying to use the derived column transform, but it doesn't appear to let me add multiple ISNULL checks.

What I am trying is:

ISNULL( [LastName] )?"": [LastName] +", " + ISNULL(  [FirstName] ) ?"": [FirstName] +" " + ISNULL( [MiddleName] ) ?"": [MiddleName]

But the Editor leaves the Expression in all Red font. If I remove the 2nd and 3rd ISNULL checks it will work, but i need to check for NULLs and replace.

Is this possible in the derived column transform?  Or, do I simply need to handle in separate sql task or in a sql update statement?  I can write the update, but was hoping to handle it all within the ssis package.

Thanks

- will

- will