The fix has just been made on the org.glite.wms/org.glite.wms.purger/src/ssl_utils.cpp, by substituting the 512 by the 1024 in the proxy_init() function.

Reproducing the problem is a little bit tricky; you need to disable the cron which periodically updates the WMS's proxy: /etc/cron.d/glite-wms-create-host-proxy.cron.
When disabled the cron, during a normal functioning of the WMS (submissions, cancel, output-retrieval) another WMS's mechanism occurs (which doesn't normally do anything if the cron is enabled): a routine in the purger (ssl_utils.cpp:proxy_init()) is invoked, and it has (in the current version of WMS) the number of 512bit for the proxy generation hard-coded.

After upgrading the rpm glite-wms-purger (which also contains another fix to WMS-113 again related to this problem of 512bits), if you disable the cron, the purger will take care of wms.proxy's update, now with 1024 bit, as needed.