xi -->webas 6.20: proxy or bapi?

Hi all,

we need to call one or two BAPIs in an R/3system (on WebAs 6.20); i.e. the scenario is: XI --> R/3(6.20).

We are not sure whether we should follow an outside-in approach by generating an ABAP proxy in the R/3 system or have an inside-out approach by using the RFC adapter in XI to call the BAPIs.

Are there any recommendations on what's suited best?

Which approach is "easier" and entails less effort?

As to WebAs 6.20 we heard about the APPINT 200_620 patch and also the recommended use of webas 6.20 kernel patch level 1253.

Are these two items mandatory requirements for proxy generation? Where can I quickly find out, whether the R/3 system has these add-ons installed?

Any help appreciated; thank you very much,

Martin.