diff --git a/elements/source-repositories/README.md b/elements/source-repositories/README.md
index f72168f0..7ed9c9b6 100644
--- a/elements/source-repositories/README.md
+++ b/elements/source-repositories/README.md
@@ -23,9 +23,17 @@ diskimage-builder which can change the details registered by the element, these
     DIB_REPOLOCATION_<name> : change the registered location
     DIB_REPOREF_<name>      : change the registered reference
 
-for example if you would like diskimage-builder to get ironic from a local
+For example if you would like diskimage-builder to get ironic from a local
 mirror you could set DIB_REPOLOCATION_ironic=git://localgitserver/ironic.git
 
+*As you can see above, the \<name\> of the repo is used in several bash
+variables. In order to make this syntactically feasible, any characters not in
+the set \[A-Za-z0-9_\] will be converted to \_*
+
+*For instance, a repository named "diskimage-builder" would set a variable called
+"DIB_REPOTYPE_diskimage_builder"*
+
+
 Alternatively if you would like to use the keystone element and build an image with
 keystone from a stable branch then you would set DIB_REPOREF_keystone=stable/grizzly
 
diff --git a/elements/source-repositories/extra-data.d/98-source-repositories b/elements/source-repositories/extra-data.d/98-source-repositories
index 61bc9618..ae08f1e2 100755
--- a/elements/source-repositories/extra-data.d/98-source-repositories
+++ b/elements/source-repositories/extra-data.d/98-source-repositories
@@ -29,15 +29,15 @@ function get_repos_for_element(){
             local REPO_SUB_DIRECTORY=$(dirname $REPO_DEST)
 
             # REPOTYPE can be overridden with DIB_REPOTYPE_{name}
-            local REPOTYPE_OVERRIDE=DIB_REPOTYPE_${REPONAME//-/_}
+            local REPOTYPE_OVERRIDE=DIB_REPOTYPE_${REPONAME//[^A-Za-z0-9]/_}
             REPOTYPE=${!REPOTYPE_OVERRIDE:-$REPOTYPE}
 
             # REPOLOCATION can be overridden with DIB_REPOLOCATION_{name}
-            local REPOLOCATION_OVERRIDE=DIB_REPOLOCATION_${REPONAME//-/_}
+            local REPOLOCATION_OVERRIDE=DIB_REPOLOCATION_${REPONAME//[^A-Za-z0-9]/_}
             REPOLOCATION=${!REPOLOCATION_OVERRIDE:-$REPOLOCATION}
 
             # REPOREF can be overridden with DIB_REPOREF_{name}
-            local REPOREF_OVERRIDE=DIB_REPOREF_${REPONAME//-/_}
+            local REPOREF_OVERRIDE=DIB_REPOREF_${REPONAME//[^A-Za-z0-9]/_}
             REPOREF=${!REPOREF_OVERRIDE:-$REPOREF}
 
             # Determine a unique cache path for this repo