The package is just a XML file, open it up in any test editor. I use Textpad for this.

For instance the reason I do the manual edit of the file is if you have lot of columns to add in the script transformation component. I would just add the all the columns (sometimes upto 150 of them in some cases) with out renaming them and the in the text editor, you can copy and paste the column names over the name "Column" "Comun 1" etc. In the Textpad editor you can also do "block selects" which makes this copy and paste a 1 step process.

So instead of adding the input and output columns in the script transformation component, renaming each of them to the correct names, changing the types, changing the size of the columns etc, you can add the required number of output columns, then in Textpad do a block select of the names you want to copy and block paste them over the generated names.

If you are carefull you can do the column type and column size as well with the block select in textpad, but i normally would do this in BIDS itself.

The XML used in 2005 and 2008 differs a bit in the formatting of the xml itself, but it still is just xml which you can edit and format as you wish.

BIDS will in anycase reformat the xml once you save the package inside it again.

BUT, as mentioned before, I've had 1 or 2 problems before in 2005, but currently on 2008 R2, and have had no problems with manual edit of the pacakges.

Hope this helps