If you cannot clean it up with the parameters in the ARIA control tab, I'd try using the individual legacy string sections in a separate ARIA instance, as they are based on a dry sample set.  The legacy section strings are pretty dry compared to the Garritan Orchestral Strings, so it may be desirable to add some reverb (the main reason I suggest doing it in a dedicated ARIA instance...so you can give the strings unique reverb settings from other ARIA instances if needed).

Don't forget that you can layer several ARIA sound-sots by setting them to the same MIDI channel.  I.E.  Load a violin, viola, cello, and contra tutti patches in different slots set to the same channel.  In fact, you can also build sections using individual/solo instruments this way as well (notice ARIA comes with something like 6 single player instruments (plr 1 - plr 3) each for violins, violas, cellos, and basses).  

I just discovered something that can really come in handy with the Garritan Orchestra strings.

CC119 will allow some real time adjustment to the attack.

Example...

Say you have a really fast legato passage and the first part of the sample's attack is just to weak to pull off the run.  Try inserting a CC119 event with a high value (say the max of 127) just before the run.

If you're using Finale you can do this with the MIDI tool.

With Sibelius you can enter expression or technique text such as:

~C119,127

If you keep using the same patch/instrument for other types of attacks you might need to change it back to 0 (or whatever you want) after the 'fast passage'.