Historische Zeitschrift Style capitalizing first letter problem

Question

I am using Historische Zeitschrift Style and the probem I have is that it capitalises some of the things it shouldn't. Let me try to explain.

Here is my MWE:

\documentclass[a4paper,11pt]{scrartcl}
\usepackage[latin1]{inputenc}
\usepackage{csquotes}
\usepackage{blindtext}
\usepackage{filecontents}
\usepackage{hyperref}
\hypersetup{
    colorlinks,
     citecolor=black,
     filecolor=black,
     linkcolor=black,
     urlcolor=black
}
\begin{filecontents}{\jobname.bib} 
@incollection{athanasius1998,
    Address = {Berlin/New York},
    Author = {{Athanasius Alexandrinus}},
    Booktitle = {Athanasius Werke - Die dogmatischen Schriften},
    Call-Number = {TH: Vb 17.02-1.1.2},
    Date-Added = {2010-10-16 13:24:30 +0200},
    Date-Modified = {2014-03-13 17:12:32 +0000},
    Editor = {Marin Tetz and others},
    Keywords = {source},
    Pages = {109-175},
    Publisher = {Walter de Gruyter},
    Read = {No},
    Series = {Urkunden zur Geschichte des Arianischen Streites 318-328},
    Shortauthor = {Ath.},
    Shorttitle = {Ar. 1},
    Title = {Oratio I contra Arianos},
    Volume = {1, Tl. 1, Lfg. 2},
    Year = {1998}}
@incollection{evagrius2011,
    Address = {Paris},
    Author = {{Evagrius Scholasticus}},
    Booktitle = {{\'E}vagre Le Scholastique: Histoire Eccl{\'e}siastique - Livres I-III},
    Call-Number = {TH: Va1.05/542},
    Date-Added = {2013-08-24 12:11:20 +0000},
    Date-Modified = {2014-03-30 11:54:31 +0000},
    Editor = {Joseph Bidez and Leon Parmentier},
    Keywords = {source},
    Publisher = {Les {\'E}ditions du Cerf},
    Series = {Sources chr{\'e}tiennes},
    Shortauthor = {Evagr.},
    Shorttitle = {h.e.},
    Title = {Historia ecclesiastica},
    Volume = {542},
    Year = {2011}}
\end{filecontents}
\usepackage[ngerman]{babel}
\usepackage[style=historische-zeitschrift, maxnames=2, hyperref=true, backref=true, backrefstyle=none, backend=bibtex,idemtracker=true]{biblatex}
\bibliography{\jobname}
%
\makeatletter
\renewbibmacro*{footcite}{%
  \global\boolfalse{cbx@loccit}%
  \global\boolfalse{cbx@seenote}% NEW!
  \ifciteseen
    {\iffieldundef{shorthand}
       {\ifthenelse{\ifciteibid\AND\NOT\iffirstonpage}
          {\usebibmacro{footcite:ibid}}
          {\usebibmacro{footcite:note}}}
       {\usebibmacro{footcite:shorthand}}}
       {\iffieldundef{usera}
         {\usebibmacro{footcite:full}}{\printnames{author}%
       \setunit{\addcomma\space}%
       \printfield{title}\isdot%
         {\setunit{\addcomma\space}%
          \usebibmacro{in:}%
          \printfield{usera}%
          \setunit*{\addspace}%
          \printfield[default]{volume}}}}
     \usebibmacro{footcite:save}}
\makeatother
%
\begin{document}
\blindtext\footcite[See][S. 56]{athanasius1998}
\blindtext\footcite[See][S. 22]{evagrius2011}
\blindtext\footcite[See][S. 11]{athanasius1998}
\blindtext\footcite[See][S. 12]{evagrius2011}
\end{document}

When I compile that this is what I get:

The letter "W" (marked with the red arrow) should here be small but because Shorttitle of that entry has a dot at the end (h.e.) it capitalises the first letter in the brackets.

If you compare it with the previous entry (Ar. 1) you will notice that that one doesn't have capital "W".

So how do I make it stop capitalising "W"? Thanks in advance for your help!