Issue with number of items in cart and non registered member's checking out

[myplace2100]

I am using vm 2.0.22a and joomla 2.5.11.Having problems with following -

1. how do i avoid adding number of quantities for the same product when "add to cart" button pressed multiple times mistakenly.There are some specific reasons to avoid it by settings if possible.

2.I disabled the ability for non registered members to check out.But when guest users clicks "add to cart" button, then in cart page clicks "check out now", it shows them the "add/edit billing info" page. After they fill billing info and click "save" nothing happens and a message is shown that they need to register to check out.It's normal but some buyers getting confused very much, although at first there is written that they need to register to checkout.So on their behalf, how do i disable the "add to cart button" if users are guests or may be in cart page the button should say "register to check out" instead of "check out now" or any other ways?.

[jenkinhill]

1.  there us a fix for this in the next version, 2.5.6 - you can test the latest RC version 2.5.4 - http://forum.virtuemart.net/index.php?topic=122785.0

2. ISTR there was a fix for registration issues after 2.0.22a - so again, check in 2.5.4

You can change button text with language overrides.

http://forum.virtuemart.net/index.php?topic=118683.0

[myplace2100]

I see updating to latest version may have some problems and my server php is not latest too.So finding other tweaks in codes.