diff --git a/doc/Makefile.am b/doc/Makefile.am
index b9696ea..698104b 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,7 +1,7 @@
SUFFIXES = .xml .html .txt .asc .1
.xml.html:
- xmlto xhtml-nochunks $<
+ xmlto --stringparam generate.consistent.ids=1 xhtml-nochunks $<
.xml.1:
xmlto man $<