icedtea-web v1.2 plugin + openjdk7 builds on linux/64, but quietly fails to load in Firefox12

[jerry2can at mailcan.com]

i'm trying to get icedtea v1.2 plugin built for openjdk7 and working in
Firefox 12 on linux/64.
 
on

uname -a
	Linux ldev 3.1.10-1.9-desktop #1 SMP PREEMPT Thu Apr 5 18:48:38
	UTC 2012 (4a97ec8) x86_64 x86_64 x86_64 GNU/Linux

with

	gcc -v
		...
		gcc version 4.7.0 20120413 [gcc-4_7-branch revision
		186417] (SUSE Linux) 

and

	javac -version
		Picked up _JAVA_OPTIONS: -Dswing.aatext=true
		-Dawt.useSystemAAFontSettings=on -Xmx512M
		javac 1.7.0_147


reading at,

	http://icedtea.classpath.org/wiki/IcedTea-Web#IcedTea-Web_1.2

		"OpenJDK7 support     Deepak Bhole     Done"

dl'ing

	wget -c
	http://icedtea.classpath.org/download/source/icedtea-web-1.2.tar.gz
	tar zxvf icedtea-web-1.2.tar.gz
	cd icedtea-web-1.2/

building,

	export MOZILLA_CFLAGS="-I/usr/local/xulrunner-sdk/include"
	export MOZILLA_LIBS="-L/usr/local/xulrunner-sdk/lib"
	./configure \
	--prefix=/usr/local/icedtea-web \
	--with-jdk-home=/usr/lib64/jvm/java-1.7.0-openjdk-1.7.0 \
	--enable-plugin
		...
		checking for MOZILLA... yes
		checking for xulrunner version... 20000000
		checking for xulrunner version... (cached) 20000000
		...
		checking for a JRE home directory...
		/usr/lib64/jvm/java-1.7.0-openjdk-1.7.0/jre
		checking for a Java virtual machine...
		/usr/lib64/jvm/java-1.7.0-openjdk-1.7.0/jre/bin/java
		...

	make
	make install
	strip --strip-unneeded
	/usr/local/icedtea-web/lib64/IcedTeaPlugin.so

	file /usr/local/icedtea-web/lib64/IcedTeaPlugin.so
		/usr/local/icedtea-web/lib64/IcedTeaPlugin.so: ELF
		64-bit LSB shared object, x86-64, version 1 (SYSV),
		dynamically linked,
		BuildID[sha1]=0xd787630f047c7058b629fa9a6a0b4ca3495d348b,
		stripped

	ln -sf /usr/local/icedtea-web/lib64/IcedTeaPlugin.so \
	       /usr/lib64/mozilla/plugins/


@ firefox launch, check @ about:plugins, there's no trace of the Java
plugin.

checking, with

	strace firefox
		...
		lstat("/usr/lib64/mozilla/plugins/IcedTeaPlugin.so",
		{st_mode=S_IFLNK|0777, st_size=45, ...}) = 0
		readlink("/usr/lib64/mozilla/plugins/IcedTeaPlugin.so",
		"/usr/local/icedtea-web/lib64/IcedTeaPlugin.so", 4095) =
		45
		lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...})
		= 0
		lstat("/usr/local", {st_mode=S_IFDIR|0775, st_size=4096,
		...}) = 0
		lstat("/usr/local/icedtea-web", {st_mode=S_IFDIR|0755,
		st_size=4096, ...}) = 0
		lstat("/usr/local/icedtea-web/lib64",
		{st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
		lstat("/usr/local/icedtea-web/lib64/IcedTeaPlugin.so",
		{st_mode=S_IFREG|0755, st_size=209296, ...}) = 0
		...
		stat("/usr/lib64/mozilla/plugins/gecko-mediaplayer.so",
		{st_mode=S_IFREG|0755, st_size=342986, ...}) = 0
		stat("/usr/local/icedtea-web/lib64/IcedTeaPlugin.so",
		{st_mode=S_IFREG|0755, st_size=209296, ...}) = 0
		stat("/usr/lib64/mozilla/plugins/gecko-mediaplayer-rm.so",
		{st_mode=S_IFREG|0755, st_size=342921, ...}) = 0
		...

there's no immediately obvious problem ...

as a first step tp deteriming if the problem is Firefox or the plugin
build, i'd like to get anything to 'squawk' verbosely enough to give me
a hint.  Is there some more verbose, telling test I can run @Firefox, or
in the plugin itself?