i have a lot of attributes to set up.
most of them only differ in another suffix: for example:

attribute1_suffix1
attribute1_suffix2
attribute1_suffix3

If I doubleklick "suffix1" in Excel the whole word "attribute1_suffix1" is
selected. This makes it very painful to process lots of data.

suggestion: offer an option to setup delimiters like in ... UltraEdit for
example.
Delimiters like {}""$<_ and so on. not only " "

This is a VBA editor issue, right? I don't know of a way to do what you
asked; but you could type your suffixes using a "uniquely findable"
character in front of them, say a backward apostrophe (on the key next to
the 1-key), and then do a Replace All on that character substituting your
attribute prefix for it. Hence, you would type

`suffix1
`suffix2
`suffix3

select Edit/Replace, put ` in the Find What field and attribute1_ in the
Replace With field and click the Replace All button. It is not what you
asked for, but it may prove to be a tolerable work-around.

Rick