Allowing special characters in facets

I am using the Apachesolr module with this. I have some custom fields that contain parenthesis, for example: 11(1)(h).
They are stored in Solr as multivalued strings.

The problem is that when you select one of these filters with the brackets in it, because Solr thinks they are special characters, it does not work.

If I manually escape them by using 11\(1\)\(h\) then it will work.

So what I started to do - I am using FacetApi Multiselect also so you can select multiple of these - is I rewrote the URL escaping the brackets, and that works.

Firstly, I don't know if there is a completely easier way of achieving all this? If I was going down the right track however, I am then presented with the problem that the facet works and shows the correct results; however the facet isn't considered "active" and therefore does not show up as being selected once the results are shown.

I've noticed that if there is a space in the facet then it works normally, e.g. AB 12 (1)(a) is fine whereas 11(1)(h) is not.

Any advice appreciated.