Manage traveling costs ??

[Max89]

Hi,
I don't know if it's the right place to ask for that, so if it's not please forgive me.
Well, what we'ld like to do in our company is to manage/ to control the "traveling costs" of our sales representatives when they go to clients. We did not find in Sugar any function close to that concept, and the design studio does not seem to do that.
What we need is a way to manage :
- a trip
- a cost/km
- extra costs (restaurants...)
and we should be able to assign these "trips" to one sale representative, and then to sum them, well to manage them...
These trips can't be linked to one opportunity for instance as in one trip, the person can visit more than one company...

So, my question is :
- did we miss something and this concept is already implemented in Sugar ?
- if not, is there a work around to do it anyway ?

Thanks in advance,
Regards,
Max.

[Max89]

Well it seems that nobody has to deal with traveling costs...
I'ld like to know what would happen if I try to modify the code to manage these costs in Sugar : in case of a release of a new version, will I have to code this functionnality again and again ? Or is available a SDK to code a new module called traveling costs for instance ?
I think that there will not be huge modifications so I'ld appreciate if you could tell me what would be the simpliest way to deal with this.
Regards,
Maxime.