Loadrunner中web_custom_request使用场景

其中有一段从服务器段动态返回的字符串需要重新提交给服务器（见红色标注）

录制自动生成的脚本是：
web_submit_data("generateYfLstAction.do", 
    "Action=http://172.32.234.213:8001/SAPIR/commission/generateYfLstAction.do", 
    "Method=POST", 
    "TargetFrame=", 
    "RecContentType=text/html", 
    "Referer=http://172.32.234.213:8001/SAPIR/commission/listCommissionAction.do", 
    "Snapshot=t10.inf", 
    "Mode=HTML", 
    ITEMDATA, 
    "Name=proc", "Value=page", ENDITEM, 
    "Name=companyCode", "Value=2000", ENDITEM, 
    "Name=tradeZone", "Value=", ENDITEM, 
    "Name=trade", "Value=", ENDITEM, 
    "Name=genDateBegin", "Value=2007-06-18", ENDITEM, 
    "Name=genDateEnd", "Value=2007-07-18", ENDITEM, 
    "Name=tradeLane", "Value=", ENDITEM, 
    "Name=actvyDateBegin", "Value=", ENDITEM, 
    "Name=actvyDateEnd", "Value=", ENDITEM, 
    "Name=svcLoopCodeBase", "Value=", ENDITEM, 
    "Name=svvdBase", "Value=", ENDITEM, 
    "Name=portCodeBase", "Value=", ENDITEM, 
    "Name=svcLoopCode", "Value=", ENDITEM, 
    "Name=svvd", "Value=", ENDITEM, 
    "Name=portCode", "Value=", ENDITEM, 
    "Name=commMode", "Value=", ENDITEM, 
    "Name=commType", "Value=", ENDITEM, 
    "Name=commClass", "Value=", ENDITEM, 
    "Name=blRefCode", "Value=", ENDITEM, 
    "Name=totalPage", "Value=1211", ENDITEM, 
    "Name=currentPage", "Value=5", ENDITEM, 
    "Name=downloadInd", "Value=0", ENDITEM, 
    "Name=page", "Value=5", ENDITEM, 
    "Name=commYfLstIds", "Value=1902189472274599&9999203000&Cargo&USD&SAL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1902189472274599&9999203000&Operation&USD&FPOL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903184294047663&9999203000&Cargo&USD&SAL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903184294047663&9999203000&Operation&USD&FPOL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1902644201920888&9999203000&Cargo&USD&SAL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1902644201920888&9999203000&Operation&USD&FPOL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903191810240974&9999203000&Cargo&USD&SAL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903191810240974&9999203000&Operation&USD&FPOL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903191810240966&9999203000&Cargo&USD&SAL&1&1", ENDITEM, 
    "Name=commYfLstIds", "Value=1903191810240966&9999203000&Operation&USD&FPOL&1&1", ENDITEM, 
    "Name=companyCode", "Value=2000", ENDITEM, 
    LAST);
    

因为这些value都是动态提交，因此需要改用web_custom_request函数
修改后的脚本如下：
web_custom_request("generateYfLstAction.do", 
     "URL=http://172.32.234.213:8001/SAPIR/commission/generateYfLstAction.do", 
      "Method=POST", 
      "Resource=0", 
      "RecContentType=text/html", 
      "Referer=http://172.32.234.213:8001/SAPIR/commission/listCommissionAction.do", 
      "Snapshot=t27.inf", 
      "Mode=HTTP", 
      "Body=proc=page&companyCode=2000&tradeZone=&trade=&genDateBegin=2007-06-18&genDateEnd=2007-07-18&tradeLane=&actvyDateBegin=&actvyDateEnd=&svcLoopCodeBase=&svvdBase=&portCodeBase=&svcLoopCode=&svvd=&portCode=&commMode=&commType=&commClass=&blRefCode=&totalPage=1206&currentPage=3&downloadInd=0&page=3&commYfLstIds=1902457907718192&9999203000&Cargo&USD&SAL&1&1&commYfLstIds=1902457907718192&9999203000&Operation&USD&FPOL&1&1&commYfLstIds="1903242276105507&9999203000&Operation&USD&FPOL&1&1&commYfLstIds=1903242276105522&9999203000&Cargo&USD&SAL&1&1&commYfLstIds=1903242276105522&9999203000&Operation&USD&FPOL&1&1&commYfLstIds=1902525553448997&9999203000&Cargo&USD&SAL&1&1&commYfLstIds=1902525553448997&9999203000&Operation&USD&FPOL&1&1&companyCode=2000", 
       LAST);

但是这个动态字符串中包含“&”，和函数中默认&代表连接符冲突，因此提交服务器端是报错。
我手工把body段的凡是commYfLstIds=后不是连接符的“&”都替换成%26，才能提交成功（手动修改后代码如下）

"Body=proc=page&companyCode=2000&tradeZone=&trade=&genDateBegin=2007-06-18&genDateEnd=2007-07-18&tradeLane=&actvyDateBegin=&actvyDateEnd=&svcLoopCodeBase=&svvdBase=&portCodeBase=&svcLoopCode=&svvd=&portCode=&commMode=&commType=&commClass=&blRefCode=&totalPage=1206&currentPage=3&downloadInd=0&page=3&commYfLstIds=1902457907718192%269999203000%26Cargo%26USD%26SAL%261%261&commYfLstIds=1902457907718192%269999203000%26Operation%26USD%26FPOL%261%261&commYfLstIds="1903242276105507%269999203000%26Operation%26USD%26FPOL%261%261&commYfLstIds=1903242276105522%269999203000%26Cargo%26USD%26SAL%261%261&commYfLstIds=1903242276105522%269999203000%26Operation%26USD%26FPOL%261%261&commYfLstIds=1902525553448997%269999203000%26Cargo%26USD%26SAL%261%261&commYfLstIds=1902525553448997%269999203000%26Operation%26USD%26FPOL%261%261&companyCode=2000", 
我是把服务器动态返回的“1902189472274599&9999203000&Cargo&USD&SAL&1&1”这类记录都进行了动态关联，因此请问大家如何才能让lr自动将动态关联所得参数中出现的“&”转义变成%26呢？