[TxMt] Conditional insertion help

[guerom00]

Hi all,

I made some snippets using conditional
insertions for my declarations in Fortran.
For example, I have this one : 

real*${1:8}${2: a/d}${2/(,a)|(,d)/(?1:llocatable)
(?2:imension)/}${2/,a|(,d)/(?1:\(\))/} :: ${3:name}${2/,d|(,a)/(?1:\(\))/}
$0

which does that : 

http://guerom00.free.fr/clutter/Cond_insert.mov

What I would like to do is, in the “allocatable” or
“dimension” case, that the caret goes between the
braces after I type in the name.
In the snippet definition, that would be to somehow
define a $4 key but I really don't know how to do this...

Any help is much appreciated :-)

PS : Once again, due to my poor knowledge of RegExp,
if anyone has some suggestions/improvements for this 
snippet, he is quite welcome :-D